Hello,
I have an Acer Nitro 5 AN515-55 with an i5-10300H and BIOS version 2.06. I attempted to undervolt the CPU using SREP, but I set the offset too aggressively (e.g., -500mV). This has caused the laptop to enter a bootloop; it powers on, the indicator lights work (e.g., charging status has logic, switches between orange and blue depending on the charge), but there’s no display output, and it repeatedly tries to reboot.
I believe the core BIOS is not corrupt, but the extreme undervolt setting is preventing the CPU/iGPU from initializing properly.
I have a CH341A programmer and an SOIC8 test clip. My goal is to:
- Identify and modify the undervolt offset value in the NVRAM to a safer value (e.g., -125mV).
- Flash the modified BIOS back to the chip.
I have already read the XMC chip and extracted the whole body of the NVRAM Volume (.vbd), Could someone please guide me on how to locate the specific core undervolt offset in the NVRAM Volume for this model/version, or if there’s a known method to revert this setting? I have the official NVRAM Volume (.vbd) file available for comparison. A fast reply would be really really helpful, since I don’t have a lot of time(maximum 3-4 days) with the CH341A Black programmer, since I borrowed it from the IT technician in my college.
Any help or advice would be greatly appreciated!
Edit (2025-06-14 00:14 AM): I got the laptop to boot after replacing the whole body of the NVRAM volume with the official Bios body from Acer’s website, still need to get the device specific data somehow onto my current .rom
Edit (2025-06-14 02:34 AM): I have fixed the bricked bios myself by just by extracting the NVRAM CpuSetup body from my bricked bios and the official bios and by copying the bytes and searching for them in the NVRAM of my bricked bios and replacing it with the CpuSetup bytes from the official Acer CpuSetup bytes, no compiling needed just some exploring in HxD (btw really wanted to use this program for awhile now and got to do it while doing myself a favour) 
Edit (2025-06-14 12:12 PM): By the way wanted to say that the amount of information this website has is crazy! Anyways, got an undervolt running on almost everything cpu related (core, cache, uncore, ring, slice, gt, etc…), here are my stable undervolts so you can try them to see if you won a sillicon lottery like me:)
