m1n1.adt: introduce yet another DAPFT8110 variant #345
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jannau
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Oct 27, 2023
proxyclient/m1n1/adt.py
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| @@ -228,7 +228,6 @@ | |||
| "unk3" / Hex(Int8ul), | |||
| "r0h" / Hex(Int8ul), | |||
| "r0l" / Hex(Int8ul), | |||
| "unk4" / Hex(Int8ul), | |||
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This depends unfortunately on the iboot version. Depending on the version we need variants with either 3 or 4 bytes of additional unknown data (maybe padding).
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Hmm, so what's the proper fix here, then? Figure out what iBoot version changed it, and check that in the parser?
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I would add this as additional variant and decide based on the length which one to use. The length of the property has to be a multiple of the element length and based on the size and typical number of elements I think we're not going to run into ambiguous situations.
alyssais
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When I tried to use the proxyclient shell, I got: "Exception parsing /device-tree/arm-io/dart-dcp.dapf-instance-0 value […]" I laid out the hex dump in a text editor, and added line breaks every 56 bytes (the former size of DAPFT8110B): 0000703b020000000080713b0200000020000000000000000000000000000000000000000000000000000000000000000003010000000000 40723b020000000080723b020000002000000000000000000000000000000000000000000000000000000000000000000301000000000000 003b020000007f73073b02000000200000000000000000000000000000000000000000000000000000000000000000030100000000000028 3d020000000040283d020000002000000000000000000000000000000000000000000000000000000000000000000301000000000080003d 020000000380003d020000002000000000000000000000000000000000000000000000000000000000000000000301000000000000e03f02 000000ffffef3f0200000020000000000000000000000000000000000000000000000000000000000000000003010000000000c0403e0200 0000ffff403e020000002000000000000000000000000000000000000000000000000000000000000000000301000000000000433e020000 00ff3f433e020000002000000000000000000000000000000000000000000000000000000000000000000301000000000000783d02000000 03417a3d0200000020000000000000000000000000000000000000000000000000000000000000000003010000000000003c3b0200000000 003e3b020000002000000000000000000000000000000000000000000000000000000000000000000301000000000000403c02000000ffff 473c020000002000000000000000000000000000000000000000000000000000000000000000000301000000000000103c020000004f0c10 3c020000002000000000000000000000000000000000000000000000000000000000000000000301000000000000703d020000000341723d 02000000200000000000000000000000000000000000000000000000000000000000000000030100000000 Looking at the patterns shared by all struct instances (r0h = 3, r0l = 1, for example), each row appeared to be shifted one byte to the left compared to its predecessor. This suggests that DAPFT8110B has only three extra bytes of padding compared to DAPFT8110. So, here I introduce DAPFT8110C, a new variant, one byte shorter than DAPFT8110B. Unlike DAPFT8110, there's no flag to differentiate between these two variants, so we just have to guess based on what divisor makes whole structs. Signed-off-by: Alyssa Ross <[email protected]>
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When I tried to use the proxyclient shell, I got:
"Exception parsing /device-tree/arm-io/dart-dcp.dapf-instance-0 value […]"
I laid out the hex dump in a text editor, and added line breaks every 56 bytes (the former size of DAPFT8110B):
Looking at the patterns shared by all struct instances (r0h = 3, r0l = 1, for example), each row appeared to be shifted one byte to the left compared to its predecessor. This suggests that DAPFT8110B has only three extra bytes of padding compared to DAPFT8110.
Removing the one byte of unknown data in the DAPFT8110B fixed the problem, allowing me to start the shell.
This seems to be how the device I have works, anyway. I'm not able to test others.