BIOS Modding: Modding bios values with set values (BIOS setup values)

I’m attempting to mod a BIOS to re-enable UEFI-boot (flash-able) on a password protected BIOS - (I forgot the password, but am selling the laptop, a Asus G74sx; received OEM system-restore CD from ASUS, but it is an UEFI-boot, which was disabled in BIOS)
I can’t boot from cd until I enable UEFI-boot… Or run through an interesting week going through possible frames of mind I could have possibly been in, typing the password in.

I’m thinking if I could flash with just that value changed, I could use the CD to clear the bios to manufacturer, according to Asus. I noticed during a (Manufacturer, ASUS image) flash that the BIOS was reset to default values, so it is something feasible, just that the BIOS password is stored on a medium that is not overwritten or is stored on a separate chip. I have MMtool, a hex editor, and Aptio software. (Been doing non-destructive testing) Currently, there is a paradigm I don’t have to interpret the hex values into something I can wrap my mind around enough to get going.

The goal here is just to change “UEFI boot” region to enabed. Are there good resources on editing ROM files, or good prereqs?


The latest BIOS for this laptop is made in 2011, it’s probably not locked at all, and if so, can be reflashed using AFU.
To reset the password you need to flash a factory BIOS with clean NVRAM and that’s it, no CDs needed.

Does it matter that I’ve attempted to clear NVRAM using the “AFUWIN64.exe /n”? Or is it that it must be done on the image prior to?

AFU tries to preserve passwords, that is why I recommend Intel FPT or flashrom as a flash tool.

Thanks! I’ll give it a try and report back!

I referenced [Guide] Flashing modified AMI Aptio UEFI using AFU and it was successful. I had some trouble when flashing with AFU because of a ROM ID mismatch. It cleared after disabling “verify ROM ID before write”. (Using manufacturers BIOS at The curiosity of what password I set will lurk in the unknowns until it pops up on a otherwise quiet, sunny Sunday afternoon.