Validating flash dumps

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Why so important?

Whenever you want to mess with flash (NAND or NOR), you have to make sure you are getting 100% correct, valid, verified dumps.

When you don't, and for some reason(s) the dump is invalid/bad, and you are rewriting to flash, you have no way of restoring the console hence making a perma-brick (unrecoverable brick).

So what can we use to prevent that, and make sure our dumps are as proper as we can check?

Visual inspection

Open up the flashdump (make it unified first if it is still 2 seperate NAND dumps) with a hexeditor (e.g. HxD) and compare what you see with the Flash page.

Only zeroes

00 00 00 00 00 00 00 00 00 where data should've been
  • Seems reading is a problem, mostly caused by bad wiring/clip seating -> check

patterned non zeroes

30 30 30 30 30 30 30 30 30 where zeroes should've been
  • Seems reading is a problem, mostly caused by bad wiring/clip seating -> check
  • Can also be caused by bad grounding, too low Vcc, interference or too long wires -> check

Repetitions

take 16 bytes of an offset that should be unique, e.g. the 0x10 offset which normaly has the DEADBEEF magic header : 

 NOR: 0x0000010 00 00 00 00 0F AC E0 FF 00 00 00 00 DE AD BE EF  //  NAND: 0x040010 00 00 00 00 0F AC E0 FF 00 00 00 00 DE AD BE EF

And find all instances in hexeditor
When it says found in 0x10 and 0x10010 you substract them (0x10010 - 0x10 = 0x10000)
So that means there is an error with setting 0x10000 (only one bit set!) low
because the programmer applies 0x10010 but the actual data on the address lines (received by the nor flash) is 0x10

Checking again with other unique 16 byte sequence

 617365637572655F6C6F616465720000 (asecure_loader in hex)

Same check, found at 0x420 and 0x10420 (0x10420-0x420 = 0x10000)

OK, you've found the pattern, now how do we deduct from that the faulty line?

address is 2 bytes. 0x10 in dump with hexeditor is in reality 0x8 on the address bus because we read 2 bytes at once
so the address is no longer 0x10000 but 0x8000
0x8000 (hexadecimal = base 16) = 1000 0000 0000 0000 (binary = base 2)
which means the 16th bit = 1, we start counting at A0, so the 16th is A15

conclusion : A15 is bad

Quick lookup table

repetition addressline 'stuck'
0x2 A0
0x4 A1
0x8 A2
0x10 A3
0x20 A4
0x40 A5
0x80 A6
0x100 A7
0x200 A8
0x400 A9
0x800 A10
0x1000 A11
0x2000 A12
0x4000 A13
0x8000 A14
0x10000 A15
0x20000 A16
0x40000 A17
0x80000 A18
0x100000 A19
0x200000 A20
0x400000 A21
0x800000 A22
0x1000000 A23
0x2000000 A24
0x4000000 A25
0x8000000 A26
0x10000000 A27
0x20000000 A28
0x40000000 A29
0x80000000 A30

Flowrebuilder

Links to versions

Flowrebuilder options

  • (NAND only) Unscramble then interleave flashes into one unified dump : Makes a single dump.bin from 2 seperate NAND flash dumps.
    • In the second step it also extract the content of the unified dump. Make sure it extracts correctly (it will give no warning if it fails!) and all the needed files are there.
  • (NAND only) Re-scramble modified dump then de-interleave it into two new flashes : Splits the single dump.bin into 2 seperate NAND flash dumps.
  • Byte reverse and extract a NOR dump file : First byte reverse the single dump.bin then extract NOR content.
  • Extract a Byte reversed NOR dump or an interleaved and unscrambled NAND dump : Extract the single dump.bin

Extracted flash content files

(make sure they are all there, flowrebuilder will not give warning when it fails!):

  • bootloader_0
  • bootloader_1
  • cCSD
  • cISD
  • creserved_0
  • cvtrm
  • eEID
  • trvk_pkg
  • trvk_prg
  • \asecure_loader\metldr
  • \ros\[two seperate folders named to FW version]\CoreOS files (19 up to 25 files, depending the FW version)

Notes: if it only extracted bootloader_0 + bootloader_1, check that both NANDs are dumped correct (known error with flashers that has bug with second NAND channel to read),

Online help

Upload your dump to a fileshare host (e.g. http://www.multiupload.com/) and join IRC ef.net in channel #ps3downgrade

Please use this method only after you first tried the above options first (so you have learned from it as well) :)

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