AMD Vega Firmware Signing

Moving this discussion from a thread where it did not belong:
The TALOS II from Raptor Systems is Interesting - comment #4


Summary

At least some Vega GPUs from AMD require firmware for the GPU to be signed by AMD. This prevents modding as well as theoretical open source GPU firmware development. AMD claims this is required in some way by Microsoft’s Secure Boot, although Secure Boot does not appear to require this in any way.


I originally found this mentioned here, about the RX Vega56:

The Validation & Security Blocks on BIOS section in

In a later video, they mention that as far as they know, such a guideline does not exist. (mentioned here)


In particular, I am saddened by the removal of the possibility for reverse-engineering the GPU firmware, like Fail0verflow did for an older AMD GPU:

Buildzoid mentioned something about loading a bios on boot on linux.

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This is the thread that they are working some of that out in. http://www.overclock.net/t/1633446/preliminary-view-of-amd-vega-frontier-edition-bios/130

Cool, this seems to be the same method @tkoham was telling me about on the other thread.

@MrTank Thank you, that is better than the thread I found:

Etherium forums (wolf0): https://forum.ethereum.org/discussion/15024/hows-it-hashin-vega-people

Though both yours and mine link to wolf9466’s post:


Huh, I did not realise that the GPU firmware was loaded from GPU-ROM to system-RAM by the CPU. However, this means that the signature checker (which we know is part of the GPU hardware) has to act before the CPU reads the firmware.

  1. GPU verifies GPU-firmware in GPU-ROM
  2. CPU reads GPU-firmware from GPU-ROM
  3. CPU writes GPU-firmware to system-RAM
  4. GPU reads GPU-firmware from system-RAM

The only way this makes sense is if there is a FIRMWARE_SIGNATURE_VALID flag somewhere. We know verification failure does not bar access to the GPU-ROM, since they could verify the GPU-ROM-flashing was successful.


A terminal shows wolf9466 using:

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just fyi, Wolf9466 is Wolf0/OhGodAPet

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