Question Maybe a deeply corrupted BIOS IC (chip)? (fingers crossed, I hope so)

[thisguyiknow]

I ran into a bit of a mess this morning with my computer most of it self inflicted- Here is the sequence- 1) I didn't like the VESA modes on my NVIDIA gpu so I hex edited the rom to add a 1920x1200 mode, upon reboot there was no video output. No worries, I have multiples of the same GPU and I backed up the original rom so one day I can reflash it back to health. I pop in the replacement GPU and I am greeted with a cmos fail screen and I go into the BIOS to make my settings changes---(The battery must be bad in the motherboard since it seems to lose it's mind after being off of AC power for a very short time) --while in the bios I don't do the obvious first tep which is to load optimized defaults I just change the cpu fan settings by using the fan calibrate mode and get it back to the quiet settings I like--- I save the bios and reboot --------unfortunately it never posts again -- it starts up and the shuts down and starts up and shuts down etc.....the LED gets to code 71 which indicates the south bridge was initialized -- I have shorted the cmos jumper attempting to clear the cmos again -- never works, pulled the battey, left unplugged --- no POST. I have removed all pcie cards, used each stick of RAM one at a time, reseated CPU etc.....it seems so unlikely but is it possible that I really screwed up my BIOS chip itself since messing around with BIOS settings is what immediately preceded the failure? I have ordered a preprogrammed chip because at this point it is the cheapest possibility -- any thoughts?

*I am slightly optimistic having found this youtube video

View: https://www.youtube.com/watch?v=gHlhF9MZW-Y


which is the same error I am receiving and it was fixed by replacing the BIOS chip

 

[kerberos_20]

Q-Code 71 is the PCH DXE SMM Initialization... DXE is a type of driver for UEFI BIOS and SMM stands for System Management Mode. And SMM has a lot to do with things like fans, reading proper temperatures from the motherboard and waking or sleeping the computer etc...
which doesnt says much
quote from wiki:

Some uses of the System Management Mode are:

• Handle system events like memory or chipset errors
• Manage system safety functions, such as shutdown on high CPU temperature and turning the fans on and off
• Security functions, such as flash device lock down require SMM support on some chipsets
• Deeper sleep power management support on Intel systems
• Control power management operations, such as managing the voltage regulator modules
• Emulate motherboard hardware that is unimplemented or buggy
• Emulate a PS/2 mouse and/or keyboard by converting the messages from USB versions of those peripherals to the messages that would have been generated had PS/2 versions of such hardware been connected (often referred to as USB legacy support)[7]
• Centralize system configuration, such as on Toshiba and IBM notebook computers
• Emulate or forward calls to a Trusted Platform Module (TPM)[8]

System Management Mode can also be abused to run high-privileged rootkits, as demonstrated at Black Hat 2008[9] and 2015.[10]

could be just missconfigured bios settings - reset CMOS or replace battery
could be just some connector not properly plugged in
try some basic troubleshoothing

"No POST", "system won't boot", and "no video output" troubleshooting checklist

"No POST", "system won't boot", and "no video output" troubleshooting checklist This checklist is a compilation of troubleshooting ideas from many forum members. It's very important to actually perform every step in the checklist if you want to effectively troubleshoot your problem. 1.Did you...

forums.tomshardware.com

 

[thisguyiknow]

Thanks for the reply -- but as stated in my post, I have already done all the basic troubleshooting

" I have shorted the cmos jumper attempting to clear the cmos again -- never works, pulled the battey, left unplugged --- no POST. I have removed all pcie cards, used each stick of RAM one at a time, reseated CPU etc....."

 

[thisguyiknow]

New BIOS chip arrived -- now it POSTed -- a cheap problem after all -- still strange but nonetheless - phew