Editing PRE-IPL

The iplloader, called "Lib-PSP iplloader" internally by Sony, also sometimes called PRE-IPL or BootROM, is the first code to run in PSP MIPS32 main CPU. Its role is to load the [[Initial Program Loader]]. iplloader contains the routines to boot into service mode and loads and decrypts the encrypted IPL from the NAND or Memory Stick.

= Location =

On retail PSP units, the iplloader is read from the [[Tachyon]]'s Allegrex MIPS R4000 based SOC boot ROM. On DTP-T1000, the iplloader is loaded externally. See also [[#Behaviour]].

The PSP main CPU is a custom-made Sony CPU with a MIPS32 core and has an embedded mask rom device (like most embedded systems do) which is exactly 4KB in size. This device holds the iplloader. This iplloader mask rom device is mapped to physical address 0x1FC00000 which is the address of reset exception vector on MIPS CPUs, and this is where the MIPS CPU starts executing from coldboot.

= Structure =

The BootROM is made up of two parts, the "bootstrap", and the "loader". It is located at physical address 0x1FC00000 and is accessed via non-cached kseg1. The ROM is accessed upon hardware reset, software reset, or NMI. When this occurs, the Status flags are set in the COP0 Status register with following bits set: Boot Exception Vector=1 and Error Level = 1. If its a hardware reset, Software Reset (SR) = 0, or if NMI or software reset it is 1. At this point the PC is set to 0xBFC00000 and it begins to execute instructions. Since this is currently in ROM mode, only registers can be modified.

= Versions =

A few examples of iplloader payload sizes and hashes are listed in the following table.

{| class="wikitable" style="text-align: center"
! Target
! SDK Version / Tachyon Revision
! Date (DD-MM-YYYY)
! Payload Size
! Hash
|-
| style="background:#C3F500"  | PSP (Retail/Testing Tool)
| style="background:#C3F500" | Tachyon 0x00140000-0x00300000
| style="background:#C3F500" | 20-04-2004 (build date in ROM)
| style="background:#C3F500" | 0xAF8
| style="background:#C3F500" | SHA-256: 48F4F11C383621C8569EC07273AE0AF6AD79681CF5B77263A69CF908EEFE4A53 (ROM)
|-
| style="background:#34D1B2" | PSP (Development Tool)
| style="background:#34D1B2" | 0.4.0
| style="background:#34D1B2" | 23-07-2004 (or older/last modified date for kbooti.bin)
| style="background:#34D1B2" | n/a
| style="background:#34D1B2" | SHA-256: 18B5BF7AEFE956D99B397AAAAC94DC965ADFDBC2BE0532096BBC1F8F8C5B7C34 (Full Binary)
|-
| style="background:#34D1B2" | PSP (Development Tool)
| style="background:#34D1B2" | 0.6.0
| style="background:#34D1B2" | 08-09-2004 (or older/last modified date for kbooti.bin)
| style="background:#34D1B2" | n/a
| style="background:#34D1B2" | SHA-256: 5CDEDDEBE11807DDAEB17BAC03945A0B828E8057C9587652CA207E3BB959AC96 (Full Binary)
|-
| style="background:#34D1B2" | PSP (Development Tool)
| style="background:#34D1B2" | 0.7.0
| style="background:#34D1B2" | 18-09-2004 (build date in the payload)
| style="background:#34D1B2" | 0x894
| style="background:#34D1B2" | SHA-256: 351ECD64C945489999D477ECAFBFBB8FE769C2484636D2F7323557F7EEFD54A2 (payload only)
 SHA-256: 388FA1DB87973A2A37D576AAAB785D840CA4D883AB5111781DA2D0AF59CFE667 (Full rebuilt binary)
|-
| style="background:#34D1B2" | PSP (Development Tool)
| style="background:#34D1B2" | 0.9.0
| style="background:#34D1B2" | 15-10-2004 (build date in the payload)
| style="background:#34D1B2" | 0x894
| style="background:#34D1B2" | SHA-256: 4F794E4FF32D5267AEAEDBA362D005EF0B7E93E29CF7C8209E0D9DBB0144F4DB (payload only)
 SHA-256: E415198C16E29D96C9232FF78272EE639D0630A56E370ED18A33D358FEF7CA95 (Full rebuilt binary)
|-
| style="background:#C3F500" | PSP (Retail)
| style="background:#C3F500" | Tachyon 0x00400000-0x00500000
| style="background:#C3F500" | 04-01-2005 (build date in ROM)
| style="background:#C3F500" | 0xB30
| style="background:#C3F500" | SHA-256: 41B2578F84BDE33E09356F0170FF99E2417EA7B1D02BD9163A41AE61FE74C3A5 (ROM)
|-
| style="background:#34D1B2" | PSP (Development Tool)
| style="background:#34D1B2" | 2.6.0
| style="background:#34D1B2" | 22-10-2005 (build date in the payload)
| style="background:#34D1B2" | 0xBF4
| style="background:#34D1B2" | SHA-256: 8821D96F5FB35C55DF649A97F5703F8A705362C2F54665B5EE4221E686B5578A (payload only)
 SHA-256: 0A83CB36F1FE7C2A9A53BD46E6FFD915D4D1BB97EED3D1EF336960DB752C3446 (Full rebuilt binary)
|-
| style="background:#34D1B2" | PSP (Development Tool)
| style="background:#34D1B2" | 2.7.1
| style="background:#34D1B2" | 14-02-2006 (build date in the payload)
| style="background:#34D1B2" | 0xBF4
| style="background:#34D1B2" | SHA-256: F9160C03EC6174F54F1C1EB645CFBBDB65B3DA47DA1A5478BE30E5EB2B0852B4 (payload only)
 SHA-256: 7DDFF7093906C10BA11D7402E9939763173F1ADEA59A38B4006484FD18EA21EA (Full rebuilt binary)
|-
| style="background:#34D1B2" | PSP (Development Tool)
| style="background:#34D1B2" | 3.5.0
| style="background:#34D1B2" | 12-02-2007 (build date in the payload)
| style="background:#34D1B2" | 0xC74
| style="background:#34D1B2" | SHA-256: AAF6F3CF0D7E028F43BE6FB788018F7A6F49B140A2591937B5C3A8373D2186A5 (payload including xor key)
 SHA-256: 5066E257EC43DA37788535C331E5A01955F5F498B103C340903409649BCB5046 (full rebuilt binary)
|-
| style="background:#C3F500" | PSP (Retail)
| style="background:#C3F500" | Tachyon 0x00600000-0x00900000
| style="background:#C3F500" | 10-09-2007 (build date in the payload)
| style="background:#C3F500" | 0xCE8
| style="background:#C3F500" | SHA-256: E511D3DC78A209610F5B3EFEA2BC64BF86B9DF14A9C279C4499FECBFD70E6BF9 (ROM)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 0.931.010-0.995.000 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 11-17-2010 (last modified date for 0.940I compat_sm.self)
| style="background:#FF8B00" | 0x2C0
| style="background:#FF8B00" | SHA-256: 6D75EC720739C53228B1CA1AFF6CE073AE542BBB38FCC9B8710EC5EB3889B942 (full binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 0.996.070-0.996.090 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 07-22-2011 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xD34
| style="background:#FF8B00" | SHA-256: E09B36DE655A441D2C94D39EF7BBC505EAB1722E9380EBE73E9E6A7DC88D9731 (full binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 1.000.041-1.06 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 08-30-2011 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xDB4
| style="background:#FF8B00" | SHA-256: C2AE6939BC4B06CB4A81415E27EB1E7129C561B9C16C3AAFF6FDEBBAB48EBD09 (Full Binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 1.50-1.81 (inside PS Vita Compatibility Security Module)
| style="background:#FF8B00" | 12-14-2011 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: 522851781DD82F89D69EBFE0F25C3E7CFE5899A53E850F2F979AD1B0E53376F9 (full binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 2.00-2.05 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 11-16-2012 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: A9A097ED8925B83A210202AA4C943011C05FE48028BA6E05E85E1494143B0100 (full binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 2.06-2.12 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 02-22-2013 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: 25E22C1D988609AA948F103E1312297F9533CA689B3C1BDC2CECBBC43997D566 (Full Binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 2.50-3.01 (inside PS Vita Compatibility Security Module)
| style="background:#FF8B00" | 06-27-2013 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: 187DD28ADAD4167F3849392D570CA5A56DEEC608156D0EC6F2453958B1DB9672 (Full Binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 3.10-3.20 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 12-05-2013 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: EF7D498295E416CCBD79FED78656E683DA1DCBC7B88C521DF0A1E00F5EC450FE (Full Binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 3.30-3.35 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 09-25-2014 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: 7DF591C05BF66292B6868CE4331A1DC11B7A0E421D082971E9CA65C7236B6843 (Full Binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 3.36-3.50 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 01-09-2015 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: 7E66976C311F5D3797A30B09DC608A0FA2E67EAA060097423CFD2E5FC89A57D9 (full binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 3.51-3.55 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 05-12-2015 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: 6E869E08CCE41E0AA0D386DE8936F81F66CABB20B964C3EF2159548852F39F30 (full binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 3.57-3.63 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 11-25-2015 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: 047366634210449C62FD813B3BFDA6267A1FA8683BA17901A214FC32E473A35F (full binary)
|-
| style="background:#FF8B00" | PS Vita
| style="background:#FF8B00" | 3.65-3.74 (inside PS Vita's Compatibility security module)
| style="background:#FF8B00" | 03-17-2017 (last modified date for compat_sm.self)
| style="background:#FF8B00" | 0xE34
| style="background:#FF8B00" | SHA-256: B5EF4FB2C84D629B2BDC9A70A4B8E5A7EC31CD9EA330E309361C80A9A96B65C5 (full binary)
|}

= Behaviour =

== iplloader Boot Sequence ==

=== Part 1 (iplloader loader) ===

Because the BootROM is stored in non-volatile read-only memory, it cannot use any variable, so the bootstrap of the BootROM copies the loader BootROM (the payload) to the CPU's scratchpad RAM. It is the only RAM available at this time, along with another 4KB block of RAM and the 2MB EDRAM — normal DDR SDRAM has not been initialised yet.

The first thing checked is the 0xBC100000 value, if non-zero, it typically means a NMI exception and it either jumps to the exception vector in COP0 Control Register $9, or if that is not set, to the exception vector in COP0 Status Register $25. On a normal reset (hardware or software), the loader code of the ROM is copied to scratch pad at physical address 0x10000 in cached mode (0x80010000). At this point, it jumps to the real BootROM loader at 0x80010000. A stack is created at 0x80013FF0 as the top of the stack. This allows to the loader to use more typical local variables and memory in addition to registers.

=== Part 2 (iplloader payload) ===

The CPU is now executes the iplloader payload from the scratchpad RAM. The iplloader payload initializes the NAND hardware and reads the IPL NAND-block-table which is a table with the physical block numbers of the encrypted IPL's location on the NAND. That table is located at the 4th physical block of the NAND i.e. at offset 0x10000, and is repeated for the next 7 blocks. This is made so that if a bad block is met, the table can still be read. However, if all 8 blocks become bad blocks, it is a non-recoverable brick because the iplloader can no longer locate the IPL. The only solution to this problem is to either boot from Memory Stick instead, or use a custom IPL to patch the iplloader to remap the table. Both solutions require a Pandora battery.

If the SysCon has set 0xBE240004's 0x10 bit, the Memory Stick is used instead of the NAND for IPL loading.

The entire raw IPL is stored on the NAND encrypted. The iplloader payload uses a 4KB RAM as a temporary location to load and decrypt each encrypted IPL block. This RAM is mapped to physical address 0x1FD00000, but is later remapped to 0x1FC00000 to be used as the ME CPU reset exception vector. Because this RAM is only 4KB in size, the encrypted IPL is organised as 4KB blocks on the NAND. As the iplloader decrypts each of the 4KB IPL blocks, it loads the decrypted blocks to the IPL entry address 0x040F0000. This address is located in the 2MB EDRAM which is normally used as VRAM. Normal DDR RAM has not been initialised yet. When the iplloader has finished decrypting and loading all the encrypted IPL blocks, it jumps to the IPL entry address.

== Memory mapping ==

The PSP iplloader is mapped to 0xBFC00000 which is the reset vector of PSP's MIPS R4000 CPU.

0.7.0 iplloader and onward are composed of two parts: a loader from 0xBFC00000 to 0xBFC0027F and a payload from 0xBFC00280 and ending at the size specified at 0xBFC000034 (little endian 0x2 bytes).

The PSP iplloader distributed in PS Vita System Software version 0.996 and onward has its payload starting at 0xBFC00180, rather than at 0xBFC00280 on previous PS Vita software and PSP hardware versions.

== DevKit behaviour ==

=== bloadp ===

bloadp is used to send kbooti binaries (encrypted iplloader data from 0x0 to 0x1000 and IPL blocks at 0x1000) to the DTP-T1000.

bloadp (through tachsm) initializes the 0x1D600000 memory (from /dev/mem or 0x00000000 from /dev/tachsm0 ; /dev/tachsm1 is mapped from 0x1D400000 to 0x1D5FFFFF) on the [http://www.psdevwiki.com/ps3/Communication_Processor Communication Processor] side (0x200000 in size, 0x100000 on the tachsm0 device) which is the DTP-T1000 PSP Shared memory, on the PSP/Tachyon side it is mapped to 0xBFE00000, it then writes the kbooti binary at 0x1D600000, however on SDK 0.5.0 and below dstdb (which bloadp was originally a part of), it was possible to specify the address to which kbooti would be loaded (default address to be specified was 0xbfc00000, the allowed range was 0xbfc00000-0xbfc10000), this in effect would write kbooti to 0x1D600000/0xBFE00000 + the address specific in the range -0xbfc00000, so for instance if 0xbfc02000 was specified, this would write kbooti to 0xBFE02000, keep in mind that the actual 0xBFC00000 memory mirrors itself every 0x1000 segments.

If bloadp is never invoked, 0x1D700000 to 0x1D7FFFFF is uninitialized memory. It is cleared out as soon as bloadp is invoked.

=== Prototype 0.4.0-0.6.0 (23-07-2004 or older) ===

The prototype iplloader reads the IPL blocks in place from 0xBFE01000 and decrypts them to 0x88400000 before jumping there. Prototype IPL blocks do not contain metadata. Instead iplloader uses 0x88400000 as a hardcoded entry point (see code samples below). In fact the IPL payload, nested inside current IPL revisions and loaded by main.bin are using the prototype format, so the prototype iplloader loads the IPL payload directly.

It is also worthy of note that the prototype iplloaders for DEM-1000 (for 0.4.0 and 0.6.0 firmwares) do not make use of physical address 0xA0010000 as their payload location. The iplloader payload is instead executed in place at 0xBFC00000. As such the iplloader data is not wiped and can be dumped in its entirety using a custom IPL. Note that the IPL format is different than later revision IPLs: prototype IPLs are loaded in a single raw Kirk commmand 1 block.

<pre>
// 0.4 iplloader
    }
    // 0xbfc00138
    function_bfc00178(100);
    uint32_t v9 = function_bfc00550(0x8400000, 0x1fe01000); // 0xbfc0014c
    // branch -> 0xbfc00154
    while (v9 < 0) {
        // 0xbfc00154
        // continue -> 0xbfc00154
    }
    // 0xbfc00158
    return unknown_88400000(-0x78000000, v8);
}
</pre>

<pre>
// 0.6 iplloader
    // 0xbfc00168
    function_bfc001b0(100);
    uint32_t v13 = function_bfc006b0(0x8400000, 0x1fe01000); // 0xbfc0017c
    // branch -> 0xbfc00184
    while (v13 < 0) {
        // 0xbfc00184
        // continue -> 0xbfc00184
    }
    // 0xbfc00188
    return unknown_88400000(-0x78000000, v9, v10, v1);
}
</pre>

=== 0.7.0-2.50 (18-09-2004) ===

The 0.7.0+ iplloader copies its payload from 0xBFC000280 to 0x80010000 i.e. physical address 0xA0010000, and jumps there. Because on DTP-T1000 0xBFC00000 is writable during the iplloader execution, and because 0xBFD00000 is an invalid range on DTP-T1000, the payload uses the 0xBFC00000 memory, which originally contains the whole iplloader as work RAM. However, it does not wipe itself so the payload is dumpable from 0xA0010000, assuming that one has code execution at IPL time.

IPL blocks are then loaded from 0xBFE01000 by the iplloader and copied to 0xBFC00000 where they are decrypted in place and copied to the location of load address specified in the metadata.

=== 2.60+ (22-10-2005) ===

Because a hash of the data stored between 0xBFC00040 and 0xBFC002C0 is used in an additional step by 2.60+ IPLs to decrypt main.bin, from 2.60 and onward the iplloader payload overwrites 0xBFC00000 with an identical copy of first 0x2C0 bytes of the original PSP-1000 (01g) iplloader ROM data. This data is stored at 0xBFC00BB0 in the 2.60 and 2.71 kbooti, 0x80010930 in the payload. The iplloader payload memsets 0x1000 bytes at 0xBFC00000 to 0 and writes the chunk there, before jumping to the IPL entrypoint. If bootstrapping the 1.50 firmware using the 2.60/2.71 iplloader part, data from the retail ROM addresses 0xBFC00200 to 0xBFC002C0 are retrievable. Note that this would not have been enough to generate the hash required to decrypt 2.60+ main.bin in any case and dumping using a custom IPL would be required to retrieve enough of the data even on a DTP-T1000.

Please note that starting from the 3.5.0 kbooti, the chunk of data written to 0xbfc00000 (which is hashed to be used as a seed for IPL part 2 decryption) changes and no longer matches any iplloader code. It is no longer code but random data.

2.6.0 kbooti also appears to fix one of the iplloader flaws that allowed to load the Pandora time attacked block. It checks for the entrypoint not to be in the 0xb* range. However, it does not check for the data size of the block.

The code that copies 0x2C0 bytes from 0x80010930 to 0xBFC0xxxx verbatim from the 2.6.0 iplloader payload:
<pre>
0x800100c4:   19 00 20 13   	beq 0x8001012c <entry_point+0x12c>, $zero, 0x8001012c <entry_point+0x12c>
0x800100c8:   00 00 00 00   	sll $zero, $zero, 0x0
0x800100cc:   8f 40 00 0c   	jal 0x8001023c <function_8001023c>
0x800100d0:   00 00 00 00   	sll $zero, $zero, 0x0
0x800100d4:   81 40 00 0c   	jal 0x80010204 <function_80010204>
0x800100d8:   00 00 00 00   	sll $zero, $zero, 0x0
0x800100dc:   c0 bf 04 3c   	lui $a0, 0xbfc0
0x800100e0:   21 28 00 00   	addu $a1, $zero, $zero
0x800100e4:   00 10 06 24   	addiu $a2, $zero, 0x1000
0x800100e8:   5a 41 00 0c   	jal 0x80010568 <function_80010568>
0x800100ec:   00 00 00 00   	sll $zero, $zero, 0x0
0x800100f0:   c0 bf 04 3c   	lui $a0, 0xbfc0 #0xbfc000000
0x800100f4:   01 80 05 3c   	lui $a1, 0x8001
0x800100f8:   30 09 a5 24   	addiu $a1, $a1, 0x930 #0x80010930
0x800100fc:   00 00 06 3c   	lui $a2, 0x0
0x80010100:   c0 02 c6 24   	addiu $a2, $a2, 0x2c0 #size of the data (0x2C0)
0x80010104:   50 41 00 0c   	jal 0x80010540 <function_80010540>
</pre>

Note that neither the 0xbfc00000 (on DTP-T1000) nor 0xa0010000 memory locations survive reboots.

=== 3.50 (12-02-2007) ===

The iplloader adds a step using a 0x40 bytes XOR key to decrypt the CMAC hash and data keys from the IPL block headers. As a result you cannot decrypt using Kirk command 1 the IPL blocks meant for the new iplloader.

The XOR key is overwritten early using a memset to 0 whenever the special Jig emulation mode is used (so the IPL block is xored by 0), this makes it impossible to obtain without glitching, knowing the kbooti CBC encryption key, knowing the xor key beforehand or using an IPL Loader exploit.

    if ( MEMORY[0xBFEFFFFC] < 0 )
    sub_800105F0(&unk_8001088C, 0, 64);

The seed for the IPL decryption (as it is used since 2.6.0) has changed to become a pseudo random 0x2C0 sized blob that is copied back from 0x800109B0 to 0xBFC00000 before jumping to the IPL entry point.
SHA-256: 1E6FC02124901F6F5A3F1BB02F065064C63E423D759A131BA1086EA8FC2D90AA

=== Development Tool Jig Memory Stick Emulation Mode ===

Starting from kbooti 0.7.0, a special Jig test mode exists. It reads an IPL block at 0x2000 on the Memory Stick instead of address 0xBFE01000 if the following condition is met:

    if ( MEMORY[0xBFEFFFFC] < 0 ) use MS

Indeed, writing 0xFFFFFFFF at 0xBFEFFFFC enables the pseudo service mode and reads the IPL block from the Memory stick. This mode is used by Sony engineers to debug Jig Memory Sticks by writing a kbooti using bloadp and then using reset parameters to set the flag at 0xBFEFFFFC using the sbootp param/arg from the reset command of either dstdb or bsreset (dspreset) such as follows: 
/usr/local/sony/bin/bootdispi/dspreset 80000000 (FFFEFFFF for example sets all boot flags to 0xFF), to set the DTP-T1000 into Jig emulation mode. 

Because flags are incremental, the only way to clear the Jig flag using official SDK tools is to run the bloadp command again as this clears the whole tachsm0 memory including the flags.

Kbooti remains loaded in memory until the main unit is turned off or bloadp has ran again, allowing then to power cycle through different memory stick.

In kbooti revision 3.5.0, this mode skips the XOR step on the Kirk header. It overwrites the XOR key with zeroes in the scratchpad. That allows one to use a regular IPL block to achieve code execution and dump the iplloader payload.

== Retail behaviour == 

The full reverse engineered assembly code can be found in uOFW: https://github.com/uofw/uofw/tree/master/src/preipl.

=== The loader ===

The loader part is almost the same for all retail PRE-IPL versions.

<pre>
ctc0($4, $v0); // save $v0
if (*0xBC100000 != 0) { // NMI interrupts enabled
    if (cfc0($9) != 0) { // NMI handler
        jump to $9;
    } else {
        $v0 = cfc0($4); // restore $v0
        // disable the BEV bit (on R4400, it moves the non-reset and NMI interruption handling to 0x80000000 instead of 0xBFC00200, but it may have a different behavior here)
        mtc0(Status, mfc0(Status) & 0xFFBFFFFF);
        jump to mfc0(EBase);
    }
} else {
    ctc0($9, 0); // reset NMI handler
    sceKernelL1IcacheInvalidateAll();
    sceKernelL1DcacheInvalidateAll();
    memcpy(0xA0010000, preipl_payload, preipl_payload_size);
    $sp = 0x80013FF0;
    sync();
    jump to 0x80010000;
}
// image ends with a copyright string, and a build timestamp: 0x20040420, 0x20050104 and 0x20070910 for successive PRE-IPL versions
</pre>

=== 01g/02g ===

pseucode from Tachyon 0x00140000-0x00300000 iplloader payload: 
<pre>
int iplBlockNumber = 0;
u32 checksum = 0;

// load/decrypt all encrypted ipl blocks
while(1)
{
// copy an encrypted ipl block to 0xBFD00000-0xBFD01000 (4KB embedded cpu ram)
if (LoadIplBlock(iplBlockNum ber, block) < 0)
while(1);

// decrypt the ipl block in place (uh oh...)
if (DecryptIplBlock(block, block))
while(1);

// first block has zero as checksum because there is no previous block (another uh oh...)
if (block->checksum != checksum)
while(1);

// load the 'data' section of the ipl block to the specified address (0x040Fxxxx range)
if (block->loadaddr)
checksum = memcpy(block->loadaddr, block->data, block->blocksize);

// reached the end of the ipl, jump to the entry address (0x040F0000)
if (block->entry)
{
// clear caches
Dcache();
Icache();

// jump to ipl - do not return
block->entry();
}

iplBlockNumber++;
}
</pre>

Tachyon revisions 0x00140000 to 0x00300000 iplloader pseudo code: 

<pre>
PSP Disassembler Ver.0.20 Copyright(c)2005,2006 BOOSTER
incl. elf-lib 0.1r2 copyright (c) 2005 djhuevo

:file name '0x80010000.bin',size = 4096
Load 3684 NID's name

:Disasm

;copied by iplloader bootcode, from 0xbfc00280-0xbfc00d78
;here code is 0x80010000 to 0x80010af8

;
;$bfd00000-$bfd00fff : sector read buffer
;

;-------------------------------------------------------
;recovery mode selector

;be240004 GPIO READ REG.
;		bit4 : device select ,0=NAND Flash,  1= rec-dev
;
;-------------------------------------------------------

;-------------------------------------------------------
;recovery boot device (rec-dev) HW assign
;
;bd200030	command register
				00009007 : read request (write size = 8)
				00002200 : read sector buffer (read size=200)
				00008004 : ? status (write size = 8 , read size=8)
				00004000 : ? status (read size=8)
				00007001 : ? (data size=8?)

;bd200034	data register (read / write)
;bd200038	status register
;			bit14:read data ready
;			bit13:parameter wirte ready
;			bit12:transmit finish ?
;			bit 9:???? error
;			bit 8:read data error
;
;bd20003c	???
			bit15:reset device ?
;
;-------------------------------------------------------


;---------------------------------------------------------------------------
;entry
;---------------------------------------------------------------------------
L80010000:
;
;reset I/O
	$800106B0(L80010a80)
;
  lui    r8,$bc10                           ;80010010[3C08BC10,'...<']
;
	if(r8[$68]>>16 == 0) $80010034
;
	r9 = r8[$78]
  ori    r9,r9,$0800                        ;80010028[35290800,'..)5']
  b      $80010040                          ;8001002C[10000004,'....']
  sw     r9,$78(r8)                         ;80010030[AD090078,'x...']
;
;80010034
  lw     r9,$7c(r8)                         ;80010034[8D09007C,'|...']
  ori    r9,r9,$0010                        ;80010038[35290010,'..)5']
  sw     r9,$7c(r8)                         ;8001003C[AD09007C,'|...']
  addiu  r4,0,$a                            ;80010040[2404000A,'...$']
  jal    $80010768                          ;80010044[0C0041DA,'.A..']
  sync                                      ;80010048[0000000F,'....']
;80010768
;
;check recovery boot mode switch
;
	r8 = [$be240004] & 0x10 // GPIO bit 4
;
	r9 = $80010194 // NAND read BLOCK entry
	r10= $80010130 // NAND initialize(read FAT) entry
;
	if(r8!=0)// $80010080
	{
		r9 = $80010248 // rec-dev read BLOCK entry
		r10= $80010240 // rec-dev initialize entry
	}
;80010080
	[$80010808] = r9
	[$8001080c] = 0x000000000
;
;call read FAT
;
	(r10)()
;
	r23 = 0  ; check sum of last block
;
;READ BLOCK LOOP
;
L80010098
	r25 = [$80010808] ; read BLOCK entry
	r4  = [$8001080c] ; block num of read
;
;call read body function
;
	r2 = (r25)(r4,$bfd000000);
	if(r2<0) $80010128
;
;decrypt 1000H block
;
	r2 = $80010620($bfd00000,$bfd00000)
	if(r2<0) $80010128
;
;+000c : check sum of last block ?
;
	if( [$bfd0000c] != r23) $80010128
;
;+0000 : distination address
;+0004 : block size
;
	r4 = [$bfd00000] ; +0000 : top pointer
	r6 = [$bfd00004] ; +0004 : size
	if(r4!=0)
	{
;transmit BLOCK body
		r23 = $80010688(r4,r16 + $10 , r6)
	}
;
;+0008 : entry point or continue MARK check
;
	r25 = r16[8]
	if(r25==0) //$80010114
	{
;L80010114:
		[$8001080c]++  ; next block
		goto $80010098
	}
;
;cache ?
	$800102D8()
;
;cache ?
	$800102A0()
;
;goto IPL entry point
;
	  jalr   r25                                ;8001010C[0320F809,'.. .']
;
;80010128
	while(1); // HALT
;
;---------------------------------------------------------------------------
;read IPL FAT
;---------------------------------------------------------------------------
L80010130:
	r16 =r31
;
;80010134
;NAND reset 
	$80010308()
;
;8001013C
	r17  = $80 // top of IPL-FAT sector
;80010140
;read IPL FAT
	r2 = $80010334(r17,8001081c,80010810)
	if(r2<0) $8001018c
;80010164
	r8 = r6[0]
	r9 = r6[4]
	r10= r6[8]
;ECC signature
	if(r9 != $6dc64a38) // $8001018c
	{
		r17 += $20 // next IPL sector
		goto $80010140
	}
; jr     r16                                ;80010184[02000008,'....']
	return

;------------------------------------------------------------------------
;NAND read body
;
;r4 : fat logical ptr (400H bytes lba? )
;
;------------------------------------------------------------------------
L80010194:
	[$80010800] = r31
	[$80010804] = r4
;
	r17 = r5
;get FAT location
	r8 = $8001081c ; FAT table
	r9 = (r4>>2)<<1
	r8 += r9
	r9 = (u16)r8[0]
;
	r8 = (r9<<2) | (r4 & 3)
;
	r16 = r8 << 3 ; * 8
	r18 = 0
;800101CC
	do
	{
;read body one
		r2 = $80010334(r16+r18,r17 + (r18<<9),80010810)
		if(r2<0) $80010230
		r8 = r6[0]
		r9 = r6[4]
		r10= r6[8]
;ECC signature
		if(r9 != $6dc64a38) $80010230
		r18++
	}while(r18<8);
;80010220
	r31 = [$80010800]
	return r0

L80010230:
	r31 = [$80010800]
	return -1

;------------------------------------------------------------------------
;rec-dev initialize
;------------------------------------------------------------------------
L80010240:
	return $800103B4()

;------------------------------------------------------------------------
;rec-dev read 1000H block
;------------------------------------------------------------------------
L80010248:
	[$80010$800] = r31
;
	r16 = r4
	r17 = r5
	r18 = 0
;8001025C
	do{
		r2 = $80010418(r18+0x10+r16<<3 ,r17 + r18<<9)
		if(r2<0) $8001025c
		r18++
	}while(r18<8);
;
	r31 = [$80010$800]
	return r2

;------------------------------------------------------------------------
;cache ?
;------------------------------------------------------------------------
L800102A0:
  mfc0   r8,Config                          ;800102A0[40088000,'...@']
  addiu  r9,0,$1000                         ;800102A4[24091000,'...$']
  dc.l   $7d081240 [invalid]                ;800102A8[7D081240,'@..}']
  sllv   r9,r9,r8                           ;800102AC[01094804,'.H..']
  mtc0   0,TagLo                            ;800102B0[4080E000,'...@']
  mtc0   0,TagHi                            ;800102B4[4080E800,'...@']
  addu   r8,0,0                             ;800102B8[00004021,'!@..']
;
  cache  $01,r8($0)                         ;800102BC[BD010000,'....']
  cache  $03,r8($0)                         ;800102C0[BD030000,'....']
  addiu  r8,r8,$40                          ;800102C4[25080040,'@..%']
  bne    r8,r9,$800102bc                    ;800102C8[1509FFFC,'....']
  nop                                       ;800102CC[00000000,'....']
  jr     r31                                ;800102D0[03E00008,'....']
  nop                                       ;800102D4[00000000,'....']

;------------------------------------------------------------------------
;cache ?
;------------------------------------------------------------------------
L800102D8:
  mfc0   r8,Config                          ;800102D8[40088000,'...@']
  addiu  r9,0,$800                          ;800102DC[24090800,'...$']
  dc.l   $7d081180 [invalid]                ;800102E0[7D081180,'...}']
  sllv   r9,r9,r8                           ;800102E4[01094804,'.H..']
  addu   r8,0,0                             ;800102E8[00004021,'!@..']
;
  cache  $14,r8($0)                         ;800102EC[BD140000,'....']
  cache  $14,r8($0)                         ;800102F0[BD140000,'....']
  addiu  r8,r8,$40                          ;800102F4[25080040,'@..%']
  bne    r8,r9,$800102ec                    ;800102F8[1509FFFC,'....']
  nop                                       ;800102FC[00000000,'....']
  jr     r31                                ;80010300[03E00008,'....']
  sync                                      ;80010304[0000000F,'....']

;----------------------------------------------------------------------------
;NAND reset CMD
;----------------------------------------------------------------------------
L80010308:
;nand cmd
	[$bd101008] = 0xff
;nand sts
	while( [$bd101004] & 1 ==0);
;
	[$bd101014] = 0x01
	return

;----------------------------------------------------------------------------
;NAND Read Sector
;
;r4 : sector
;r5 : data buffer
;r6 : Extra buffer
;
;----------------------------------------------------------------------------
L80010334:
;nand sts
	while([$bd101004] & 1 == 0);
;
	[$bd101020] = r4 << 10
	[$bd101024] = $301
;80010354
	while([$bd101024] & 1 == 0);
;80010364
	if([$bd101028] != 0) return -1
;
  lui    r8,$bff0                           ;80010370[3C08BFF0,'...<']
;
	r9  = r8[$900]
	r10 = r8[$904]
	r2  = r8[$908]
;
	r6[0] = r9
	r6[4] = r10
	r6[8] = r2
;
	r9 = r5
	r2 = $200
L80010394:
	do
	{
		r10 = r8[0]
		r2 -= 4
		r8 += 4
		r9[0] = r10
		r9 += 4
	}while(r2);
;800103AC
	return 0

;----------------------------------------------------------------------------
;rec-dev initialize
;----------------------------------------------------------------------------
L800103B4:
	r24 = r31
;
;rec-dev I/O init : device & clock enable ?
	$800106B0(L80010ad4)
;
;reset device ?
;
	[$bd20003c] = $8000
;800103D4
	while( [$bd20003c] & 0x8000);
;
	$80010530()
	$80010508()
;
;800103F4
	do{
		r2 = $800105B8()
		if(r2<0) continue // $800103f4
;
	}while(r2 & $0080 == 0); // $800103f4
;
;  jr     r24                                ;80010410[03000008,'....']
	return 0

;----------------------------------------------------------------------------
;rec-dev read sector one
;
;a1:sector address
;a2:buffer
;
;----------------------------------------------------------------------------
L80010418:
	r14 = r5
;	r24 = r31
;  lui    r25,$bd20
;
;read sector COMMAND ?
	[$bd200030] = $00009007
;
  dc.l   $7c0428e0 [invalid]                ;8001042C[7C0428E0,'.(.|']
;
	r5 >>= 8
	r9 = (r4 >> 24) << 24
;
	r4 = $00010020
	r4 |= r9
;
;write parameter
	r2 = $800104C0(r4,r5)
	if(r2<0) return -1
;busy wait
	$80010608()
;
;$8001045c
	do{
		r2 = $800105B8()
		if(r2<0) return -1
		r2 = r2 & $0020
	}while((r2 & $0020)==0);
;
	if(r2 & $0040) return -1
;
;read buffer COMMAND ?
	[$bd200030] = $00002200
;
;read sector data
	r2 = $800104CC(r14,$200) // r14 == r5
	if(r2<0) return -1
;wait finish
	r2 = $80010508()
	if(r2<0) return -1
;busy wait
	$80010608()
;
	goto $800103f4
;
;800104B8
;  jr     r24                                ;800104B8[03000008,'....']
	return -1

;----------------------------------------------------------------------------
;rec-dev : commmand output ?
;
;a1:1st write data
;a2:2nd write data
;----------------------------------------------------------------------------
L800104C0:
	[$bd200034] = r4
	[$bd200034] = r5
	goto $80010508

;----------------------------------------------------------------------------
;rec-dev read data block
;
;a1:distination pointer
;a2:transmit size
;
;----------------------------------------------------------------------------
L800104CC:
	do{
		do{
			r9 = [$bd200038]
			if(r9 & $0100) return -1;
		}while(r9 & $4000 == 0);
;
		r2 = [$bd200034]
		r5 -= 4
		r4[0] = r2
		r4 += 4
	}while(r5 >=0);
;
	return 0;

;----------------------------------------------------------------------------
;wait for TX finish ?
;----------------------------------------------------------------------------
L80010508:
	do{
		r9 = [$bd200038]
	}while(r9 & $1000 == 0);
;
	if(r9 & $0300) return -1// $80010528
;
	return 0

;----------------------------------------------------------------------------
;rec-dev read status ?
;----------------------------------------------------------------------------
L80010530:
;  addu   r15,r31,0                          ;80010530[03E07821,'!x..']
;  lui    r25,$bd20                          ;80010534[3C19BD20,' ..<']
;
	[$bd200030] = $00008004
	[$bd200034] = $06100800
	[$bd200034] = 0
	r2 = $80010508()
	if(r2<0) return -1
;
	$800105A4($80010a1c,8);
;
;get status ?
;
	r4 = [$80010a1c]
	r5 = [$80010a20]
;
	if( (r4>>16)&0x15 != 0) return -1
;
	return 0

;----------------------------------------------------------------------------
;rec-dev read status ?
;
;a1:buffer
;a2:size
;
;----------------------------------------------------------------------------
L800105A4:
	[$bd200030] = $00004000
;read sector body
	return $800104cc(r4,r5)

;-----------------------------------------------------------------------------
;rec-dev device ready check?
;-----------------------------------------------------------------------------
L800105B8:
;r25 = $bd200000
	[$bd200030] = $00007001
;wait
	do
	{
		r9 = [$bd200038]
	}while(r9 & $0100);
	if((r9 & $4000)==0) $800105c0
;
	r2 = [$bd200034]
	r0 = [$bd200034] // ?
;800105E0
	do{
		r9 = [$bd200038]
		if(r9 & $0100) //$80010600
		{
L80010600:
			return -1
		}
	}while( (r9 & $1000)==0);
;
	return r2 & 0xff;

;----------------------------------------------------------------------------
;wait for rec-dev busy
;----------------------------------------------------------------------------
L80010608:
	do
	{
		r9 = [$bd200038]
	}while( (r9 & $2000) == 0);
	return

;-----------------------------------------------------------------------------
;decrypt 1000H block
;-----------------------------------------------------------------------------
L80010620:
;  lui    r25,$bde0                          ;80010620[3C19BDE0,'...<']
;
	[$bde00010] = $00000001
;r8 = r4
  dc.l   $7ca8e000 [invalid]                ;8001062C[7CA8E000,'...|']
	[$bde0002c] = r8
;
;r8 = r5
  dc.l   $7c88e000 [invalid]                ;80010634[7C88E000,'...|']
	[$bde00030] = r8
;
	[$bde0000c] = $00000001
;$80010644
	do{
		r8 = [$bde0001c]
	}while(r8 & $0011 == 0)
;
	[$bde00028] = r8
	if(r8&$0010) // $80010664
	{
L80010664:
		[$bde0000c] = $00000002
;$8001066C
		do{
			r8 = [$bde0001c]
		}while(r8 & $0002 == 0)
;
		[$bde00028] = r8
		sync
		return -1
	}
;
	return [$bde00014]

;----------------------------------------------------------------------------
;transmit data with calc check sum
;
;arg1: source
;arg2: distination
;arg1: size
;
;return : 32bit check sum (add)
;
;----------------------------------------------------------------------------
L80010688:
	r2 = 0 ; clear check sum
	do{
		r3 = r5[0]
		r5 += 4
		r6 -= 4
		r4[0] = r3
		r2 += r3 ; check sum
		r4 += 4
	}while(r6>=0);
	return

;---------------------------------------------------------------------------
;script executer
;
;a1:script pointer
;
;2 word command
;
;+00[31:28] : CMD
;+00[27: 0] : OFFSET
;+04[31: 0] : VALUE
;
;CMD : command :
; 0  : store   | [$b0000000 + OFFSET]  = VALUE
; 1  : or      | [$b0000000 + OFFSET] |= VALUE
; 2  : and     | [$b0000000 + OFFSET] &= VALUE
; 3  : wait toL| while( ( [$b0000000 + OFFSET] &= VALUE) != 0)
;(4) : wait toH| while( (~[$b0000000 + OFFSET] &= VALUE) != 0)
; 5  : delay   | for(cnt=VALUE*96;cnt;cnt--)
; F  : end     | return
;
;---------------------------------------------------------------------------
L800106B0:
	r8 = r4
;addu   r25,r31,0
;
;800106b8
	do{
		// read CMD:offset + VALUE
		r4 = r8[0]
		r9 = r4 >> 28
		r4 = ( (r4 << 4)>>4 ) | $b0000000
		r5 = r4[4]
;
		if(r9==0) //$80010724
		{
;80010724
			r4[0]=r5
			goto $8001071c
		}
		if(r9==1)// $8001072c
		{
;8001072C
			r4[0] = r4[0] | r5
			goto $8001071c
		}
		if(r9==2) // $8001073c
		{
			r4[0] = r4[0] & r5
			goto $8001071c
		}
		r1 = 0
		if(r9==3) $8001074c
;
		r1 = $ffffffff ;  nor    r1,0,0
;!!!!! buggy code !!!!!
;  addiu  r10,r10,-$4
;		if(r9==4) $8001074c
		if(r9==7) $8001074c
;!!!!! buggy code !!!!!

;		if(r9==5) //$80010714
		{
L80010714:
			$80010768(r5);
			goto L8001071C
		}
;default:
;  jr     r25                                ;8001070C[03200008,'.. .']
		return;
;
;case end
L8001071C:
		// next script point
		r8 += 8
	}while(1);
;
;4,7
L8001074C:
	{
		do{
			r9 =  (r4[0] ^ r1) & r5
		}while(r9!=0);
		goto $8001071c
	}

;--------------------------------------------------------------------------
;delay
;--------------------------------------------------------------------------
L80010768:
	r1 = ((r4 << 1) + r4)<<5 // * 96
	while(r1) r1--;
	return

;--------------------------------------------------------------------------
;--------------------------------------------------------------------------
L80010784:
  nop                                       ;80010784[00000000,'....']
  nop                                       ;80010788[00000000,'....']
  nop                                       ;8001078C[00000000,'....']
  nop                                       ;80010790[00000000,'....']
  nop                                       ;80010794[00000000,'....']
  nop                                       ;80010798[00000000,'....']
  nop                                       ;8001079C[00000000,'....']
  nop                                       ;800107A0[00000000,'....']
  nop                                       ;800107A4[00000000,'....']
  nop                                       ;800107A8[00000000,'....']
  nop                                       ;800107AC[00000000,'....']
  nop                                       ;800107B0[00000000,'....']
  nop                                       ;800107B4[00000000,'....']
  nop                                       ;800107B8[00000000,'....']
  nop                                       ;800107BC[00000000,'....']
  nop                                       ;800107C0[00000000,'....']
  nop                                       ;800107C4[00000000,'....']
  nop                                       ;800107C8[00000000,'....']
  nop                                       ;800107CC[00000000,'....']
  nop                                       ;800107D0[00000000,'....']
  nop                                       ;800107D4[00000000,'....']
  nop                                       ;800107D8[00000000,'....']
  nop                                       ;800107DC[00000000,'....']
  nop                                       ;800107E0[00000000,'....']
  nop                                       ;800107E4[00000000,'....']
  nop                                       ;800107E8[00000000,'....']
  nop                                       ;800107EC[00000000,'....']
  nop                                       ;800107F0[00000000,'....']
  nop                                       ;800107F4[00000000,'....']
  nop                                       ;800107F8[00000000,'....']
  nop                                       ;800107FC[00000000,'....']

;-----------------------------------------------------------------------------
;
;r31 save buffer
;
L80010800:
	dl 800100B0

;
;r4 save buffer
;
L80010804:
	dl 0000002E
;
;read sector function entry
;
L80010808:
	dl L80010194
;
;read block number
;
L8001080C:
	dl L0000002E
;
;NAND Extra buffer
;
L80010810:
	dl	FFFFFFFF
	dl	6DC64A38
	dl	FFFFFD89

;
;NAND Data buffer (IPL FAT)
;
L8001081c
  mfhi   0                                  ;8001081C[00110010,'....']
  mflo   0                                  ;80010820[00130012,'....']
  dsllv  0,r21,0                            ;80010824[00150014,'....']
  dsrlv  0,r23,0                            ;80010828[00170016,'....']
  mult   0,r25                              ;8001082C[00190018,'....']
  div    0,r27                              ;80010830[001B001A,'....']
  nop                                       ;80010834[00000000,'....']
  nop                                       ;80010838[00000000,'....']
  nop                                       ;8001083C[00000000,'....']
  nop                                       ;80010840[00000000,'....']
  nop                                       ;80010844[00000000,'....']
  nop                                       ;80010848[00000000,'....']
  nop                                       ;8001084C[00000000,'....']
  nop                                       ;80010850[00000000,'....']
  nop                                       ;80010854[00000000,'....']
  nop                                       ;80010858[00000000,'....']
  nop                                       ;8001085C[00000000,'....']
  nop                                       ;80010860[00000000,'....']
  nop                                       ;80010864[00000000,'....']
  nop                                       ;80010868[00000000,'....']
  nop                                       ;8001086C[00000000,'....']
  nop                                       ;80010870[00000000,'....']
  nop                                       ;80010874[00000000,'....']
  nop                                       ;80010878[00000000,'....']
  nop                                       ;8001087C[00000000,'....']
  nop                                       ;80010880[00000000,'....']
  nop                                       ;80010884[00000000,'....']
  nop                                       ;80010888[00000000,'....']
  nop                                       ;8001088C[00000000,'....']
  nop                                       ;80010890[00000000,'....']
  nop                                       ;80010894[00000000,'....']
  nop                                       ;80010898[00000000,'....']
  nop                                       ;8001089C[00000000,'....']
  nop                                       ;800108A0[00000000,'....']
  nop                                       ;800108A4[00000000,'....']
  nop                                       ;800108A8[00000000,'....']
  nop                                       ;800108AC[00000000,'....']
  nop                                       ;800108B0[00000000,'....']
  nop                                       ;800108B4[00000000,'....']
  nop                                       ;800108B8[00000000,'....']
  nop                                       ;800108BC[00000000,'....']
  nop                                       ;800108C0[00000000,'....']
  nop                                       ;800108C4[00000000,'....']
  nop                                       ;800108C8[00000000,'....']
  nop                                       ;800108CC[00000000,'....']
  nop                                       ;800108D0[00000000,'....']
  nop                                       ;800108D4[00000000,'....']
  nop                                       ;800108D8[00000000,'....']
  nop                                       ;800108DC[00000000,'....']
  nop                                       ;800108E0[00000000,'....']
  nop                                       ;800108E4[00000000,'....']
  nop                                       ;800108E8[00000000,'....']
  nop                                       ;800108EC[00000000,'....']
  nop                                       ;800108F0[00000000,'....']
  nop                                       ;800108F4[00000000,'....']
  nop                                       ;800108F8[00000000,'....']
  nop                                       ;800108FC[00000000,'....']
  nop                                       ;80010900[00000000,'....']
  nop                                       ;80010904[00000000,'....']
  nop                                       ;80010908[00000000,'....']
  nop                                       ;8001090C[00000000,'....']
  nop                                       ;80010910[00000000,'....']
  nop                                       ;80010914[00000000,'....']
  nop                                       ;80010918[00000000,'....']
  nop                                       ;8001091C[00000000,'....']
  nop                                       ;80010920[00000000,'....']
  nop                                       ;80010924[00000000,'....']
  nop                                       ;80010928[00000000,'....']
  nop                                       ;8001092C[00000000,'....']
  nop                                       ;80010930[00000000,'....']
  nop                                       ;80010934[00000000,'....']
  nop                                       ;80010938[00000000,'....']
  nop                                       ;8001093C[00000000,'....']
  nop                                       ;80010940[00000000,'....']
  nop                                       ;80010944[00000000,'....']
  nop                                       ;80010948[00000000,'....']
  nop                                       ;8001094C[00000000,'....']
  nop                                       ;80010950[00000000,'....']
  nop                                       ;80010954[00000000,'....']
  nop                                       ;80010958[00000000,'....']
  nop                                       ;8001095C[00000000,'....']
  nop                                       ;80010960[00000000,'....']
  nop                                       ;80010964[00000000,'....']
  nop                                       ;80010968[00000000,'....']
  nop                                       ;8001096C[00000000,'....']
  nop                                       ;80010970[00000000,'....']
  nop                                       ;80010974[00000000,'....']
  nop                                       ;80010978[00000000,'....']
  nop                                       ;8001097C[00000000,'....']
  nop                                       ;80010980[00000000,'....']
  nop                                       ;80010984[00000000,'....']
  nop                                       ;80010988[00000000,'....']
  nop                                       ;8001098C[00000000,'....']
  nop                                       ;80010990[00000000,'....']
  nop                                       ;80010994[00000000,'....']
  nop                                       ;80010998[00000000,'....']
  nop                                       ;8001099C[00000000,'....']
  nop                                       ;800109A0[00000000,'....']
  nop                                       ;800109A4[00000000,'....']
  nop                                       ;800109A8[00000000,'....']
  nop                                       ;800109AC[00000000,'....']
  nop                                       ;800109B0[00000000,'....']
  nop                                       ;800109B4[00000000,'....']
  nop                                       ;800109B8[00000000,'....']
  nop                                       ;800109BC[00000000,'....']
  nop                                       ;800109C0[00000000,'....']
  nop                                       ;800109C4[00000000,'....']
  nop                                       ;800109C8[00000000,'....']
  nop                                       ;800109CC[00000000,'....']
  nop                                       ;800109D0[00000000,'....']
  nop                                       ;800109D4[00000000,'....']
  nop                                       ;800109D8[00000000,'....']
  nop                                       ;800109DC[00000000,'....']
  nop                                       ;800109E0[00000000,'....']
  nop                                       ;800109E4[00000000,'....']
  nop                                       ;800109E8[00000000,'....']
  nop                                       ;800109EC[00000000,'....']
  nop                                       ;800109F0[00000000,'....']
  nop                                       ;800109F4[00000000,'....']
  nop                                       ;800109F8[00000000,'....']
  nop                                       ;800109FC[00000000,'....']
  nop                                       ;80010A00[00000000,'....']
  nop                                       ;80010A04[00000000,'....']
  nop                                       ;80010A08[00000000,'....']
  nop                                       ;80010A0C[00000000,'....']
  nop                                       ;80010A10[00000000,'....']
  nop                                       ;80010A14[00000000,'....']
  nop                                       ;80010A18[00000000,'....']
;
;rec-dev status read buffer ?
L80010A1C:
	dl	00000000,00000000
;
  nop                                       ;80010A24[00000000,'....']
  nop                                       ;80010A28[00000000,'....']
  nop                                       ;80010A2C[00000000,'....']
  nop                                       ;80010A30[00000000,'....']
  nop                                       ;80010A34[00000000,'....']
  nop                                       ;80010A38[00000000,'....']
  nop                                       ;80010A3C[00000000,'....']
  nop                                       ;80010A40[00000000,'....']
  nop                                       ;80010A44[00000000,'....']
  nop                                       ;80010A48[00000000,'....']
  nop                                       ;80010A4C[00000000,'....']
  nop                                       ;80010A50[00000000,'....']
  nop                                       ;80010A54[00000000,'....']
  nop                                       ;80010A58[00000000,'....']
  nop                                       ;80010A5C[00000000,'....']
  nop                                       ;80010A60[00000000,'....']
  nop                                       ;80010A64[00000000,'....']
  nop                                       ;80010A68[00000000,'....']
  nop                                       ;80010A6C[00000000,'....']
  nop                                       ;80010A70[00000000,'....']
  nop                                       ;80010A74[00000000,'....']
  nop                                       ;80010A78[00000000,'....']
  nop                                       ;80010A7C[00000000,'....']
;
;
;script command : I/O init
;
L80010A80:
	dl	1C100058,00800000	; [$bc100058] |= 00800000
	dl	1C100050,0000608E	; [$bc100050] |= 0000608E
	dl	2C10004C,FFFFFBF7	; [$bc10004C] &= FFFFFBF7
	dl	1C100078,00000002	; [$bc100078] |= 00000002
	dl	2E240000,FFFFFFEF	; [$be240000] &= FFFFFFEF : GPIO bit4 direction read?
	dl	1E240040,00000010	; [$be240040] |= 00000010 : GPIO bit4 pullup enable ?
	dl	50000000,00000001	; delay 1
	dl	0D500010,00000001	; [$bd500010] = 00000001
	dl	3D500010,00000001	; while( [$bd500010] & 1)
	dl	0D500040,00000001	; [$bd500040] = 00000001
	dl	F0000000			; end
;
;script command : rec-dev I/O init
;
L80010AD4:
	dl	3D500010,00000001	; while( [$bd500010] & 1)
	dl	1C100054,00000100	; [$bc100054] |= 00000100
	dl	1C100050,00000400	; [$bc100050] |= 00000400
	dl	1C100078,00000010	; [$bc100078] |= 00000010
	dl	2C10004C,FFFFFEFF	; [$bc10004C] &= FFFFFEFF
	dl	F0000000			; end
;
;------------------------------------------------------------------------------
;code end
;------------------------------------------------------------------------------
</pre>

=== 03g+ === 

Known changes from earlier Tachyon ROM Revisions: 

* IPL Load address now blacklists the CPU Scratchpad range (0x80010000/0xA0010000)
<pre>
ROM:8001016C                 ext     $t0, $a0, 0x10, 0xD
ROM:80010170                 xori    $t0, 1
ROM:80010174                 beqz    $t0, loc_800101F0
</pre>

* IPL Entrypoint address now blacklists specific ranges (0xBFD00000...)

* IPL blocks now must have a minimum size of 0x100 bytes

* Kirk command 1 ECDSA is now enforced on IPL blocks

* The last 0x20 bytes of the block contain a SHA1 hash encrypted with Kirk command 7 0x6C

The block hash is calculated using
 <pre>
sha1(block[ 8 : ] + block [ : 8])
 </pre>
The first 8 bytes of the payload are copied to the end before the block is hashed.

The last block hash remains in memory and is xored in each SHA1 for each block, the result is used for the hash compare in the Kirk command 0x10 ECDSA check.

* Kirk command 0x11 ECDSA check using a custom public key (stored inside the ROM) and the xored SHA1 sum of all blocks in the hash compare function, signature present in the last IPL block (entrypoint != 0)

* The first 0x10 bytes of IPL blocks are xored using a XOR key (stored in ROM and selected from an index written by updater on nand, index 1 is used for all targets except 05g, 05g uses index 2). The XOR step is not performed when Jig/Service Mode is enabled, to allow compatibility of the Jig Memory Stick across all devices.

== PS Vita Compatibility mode behaviour == 

On PS Vita, PSP iplloader is sent by the Compatibility security module (os0:sm/compat_sm.self) to the non-secure ARM kernel which writes it to 0xE8100000 (named CompatSharedSram and mapped to the 0xBFC00000 reset vector on the emulated PSP/Tachyon side).

compat_sm then sends a specific 0x40-bytes XOR key to be used by the PS Vita's iplloader as a 0x40 bytes XOR mask against the IPL header. The IPL is stored in the pcbc.skprx kernel module.

Kirk command 1 is then used on the result. Unlike on actual PSP units, the IPL is decrypted in a single large block rather than in multiple blocks.

The 0x40 bytes key gets updated depending on the firmware version in use.

A 0x40 bytes XOR mask is also part of the 3.50+ DTP-T1000 security. See PSP iplloader section.

= Dumper =

As of March 21st 2018, a dumper for DTP-T1000 iplloader has been made available on github by mathieulh:
* [https://github.com/mathieulh/DTP-T1000-Pre-IPL-dumper]

= See also =

* [https://web.archive.org/web/20090826053327/http://silverspring.lan.st/NPSPTD_01.txt iplloader and IPL descriptions by SilverSpring]