r/ComputerEngineering • u/Darkscythe1650 • 9h ago
Can a NVRAM mod bypass a hardware-asserted PROCHOT# from a corroded pull-up resistor? (Airmont, Pentium N3710)
I've been trying to fix an old laptop of mine (Acer Aspire ES1-531-P7KK) for a while now. It'd been locked to 0.48GHz, only clocking up to higher speeds temporarily while idle occasionally (though that could be due to the kernel simply reporting last requested frequency when the core wasn't in deep-idle C state). I isolated the assertion to a bunch of corroded resistors. I don't have the skill to replace 0402SMD resistors, nor do I have the tools for it, so I began tracing how the throttling mechanism works. I dumped my BIOS, ran it through UEFITool, extraced the PE32 Image Section, and found two IFR pages that had mentions of "PROCHOT", which I've attached.

and

So I tried booting into a UEFI shell and writing to NVRAM with setup_var.efi, but I got a Write Protection error. The BIOS lock is disabled ("Enable or Disable BIOS SPI region write protect," according to the extracted IFR), so I genuinely don't know what to do. Is there any other trick that I can try, or do I need to get my hands on a pi pico, logic shifter, SOIC8 clip, 3.3V to 1.8V DC, etc, and extract the BIOS, modify it to expose the hidden settings, and flash it back?