Optimized Defaults change in Aero / Aorus BIOS after Undervolt crash?

First of all, I would like to thank everybody who contributed to this great forum. I am new here and this is my first message.
I have a Gigabyte AERO 17 laptop with i9-10980HK. I carefully followed instructions Lost_N_BIOS posted on various threads here, then unlocked hidden pages in my dumped bios and flashed the unlocked BIOS. The purpose was to see if I could undervolt this chip.

So in my MOD BIOS I went to Advanced >> OverClocking Performance Menu and set it to Enabled. I left XTU Interface Disabled following advice from member @bitobsession [win-raid dot com/t7023f54-Gigabyte-AORUS-G-XB-BIOS-unlock-Request-HELP-5.html#msg127079].

So at this pont, the only changes that I made from the original default settings in the BIOS were two: (1) Deleted all Secure Boot Variables on the Security tab to disable Secure Boot (that was before I flashed MOD BIOS); and (2) enabled OverClocking Performance Menu in Advanced tab once the mod BIOS was flashed. I did not make any other changes in BIOS.

I booted into Windows, opened ThrottleStop, and I could see that all the undervolting menus were unlocked. I wanted to find optimal CPU and cache offset values for my undervolt, and I thought TS was the safest option (since you can choose “Do not save values”). I went in small increments of just 10mV from 0 to -120mV for CPU and cache using TS benchmaks, cinebench, Prime95, OCCT, etc. Also, I experimented with different offsets for CPU and cache. I did not get any errors (that would have given me heads up), but the system did crash a few times after which it would reboot. After mapping out a perimeter for safe undervolt, I thought it would be a good idea to load “Optimised defaults” in BIOS.

So in BIOS: press F9 to load defaults, then F10 to save and exit, reboot. Then back into BIOS: Delete all Secure Boot Variables; and Advanced >> OverClocking Performance Menu >> Enabled. Boot into windows, but now all the undervolt options in ThrottleStop are marked “Locked”. I even went back into BIOS again: Advanced >> OverClocking Performance Menu >> XTU Interface >> Enabled. Reboot. Still everything is Locked in ThrottleStop (which is how it was with OEM BIOS). In other words, it looks like my settings in BIOS are simply being ignored after I loaded defaults.

Can anybody explain to me what happened?

Just out of curiocity I did: fptw.exe -bios -d biosreg.bin

I then extracted Setup and AMITSE regions from biosreg.bin and compared them with the ones in the unlocked BIOS that I flashed and they are identical. Also, I would like to point out that no software or hardware was installed, no changes to win10, the laptop is not even connected to the internet.

In researching these pages I found one member, @RS201 who reported a similar incident after an undervolt crash with his Aorus 15 [win-raid dot com/t7023f54-Gigabyte-AORUS-G-XB-BIOS-unlock-Request-HELP-1.html#msg120961].

Did the crash change BIOS defaults? How do I make these OverClocking Performance Menu settings work again (they are there in my Advanced page in BIOS but they don’t seem to do anything)?

Well, here I am answering my own message. The problem I encounted had little to do with the mod BIOS, but it had to do with consequences of undervolt crashes. As I found out, an undervolt crash may result in severe data corruption. Also, each crash is unique in what will/won’t be affected; in my case some core operating system files were corrupted and had to be restored. Once that was done, I reflashed my mod BIOS and regained the functionality to control overclocking performance menu.

As a side note, I’ll go out on a limb and say this: if anybody is looking to decrease their CPU temp via undervolt (while leaving the turbo on), good luck with that in a slim laptop like Gigabyte Aero (and possibly bigger ones too)! While a stable undervolt may increase cpu performance resulting in it spending more time at higher clocks, the cooling system in the laptop is simply not powerful enough to remove the intense heat CPU is capable of producing.