[Problem] NVRAM appears to be hosed on a GPD Win Max (Intel Ice Lake handheld PC)

This computer is a 2020 Intel laptop running an i5-1035G7 and an AMI BIOS.

I have flashed it numerous times to update the BIOS, but evidently a recent attempt was the “last straw,” and I am now experiencing weird issues with some BIOS settings and NVRAM. Specifically:

  1. Speed shift is permanently disabled in BIOS.

  2. I am unable to flash any BIOS from inside Windows. AFU gives “18 - Error: Secure Flash Rom Verify fail.” FPT appears to flash successfully, but then after a reboot the computer is bricked.

  3. I can flash a certain version of the BIOS using my CH341A programmer and the computer will work again. Only one version of the BIOS works this way: 1.16, however I can flash variations on 1.16, including versions for different RAM speeds. However, older versions, 1.11, will not work after flashing this way. Black screen.

  4. I have been trying to use AMISCE to inspect NVRAM and possibly update BIOS settings, however, whenever I dump NVRAM, there is hardly anything there. No settings (exposed or hidden). The raw dump only shows:


In spite of that, I find I am able to get into the BIOS menu and change settings just fine, e.g., the boot order.

At minimum, I would like to get Speed Shift enabled in BIOS again. But ideally I would like to get things back to normal. But I suspect something may have gotten seriously corrupted here. Thanks in advance for any advice.