Question BIOS bricked after turning on/off Secure Boot many times ?

[Semcraft]

Hello everyone,

Before starting, I'm using the HP EliteDesk 800 G2 Tower PC as my server (Proxmox) with :
- The default motherboard (this one)
- I5-6500
- 2x4GB + 1x8GB (the computer is working with this config)
- 1 x SSD SATA
- 2 x HDD

This is the actual config that was working till I encountered the problem.
https://i.ibb.co/k5HH4KY/IMG-4411.jpg
https://i.ibb.co/s6M13T9/IMG-4414.jpg

I've been using this configuration for almost 2 years 24/7 but my older SSD started to lose sectors so I had to change.
I've retired old disks and added new ones together with a GPU for which I don't have yet the new PSU but the PC is starting without problem when just plugged in the PCI slot.

Since I was running Proxmox 7, I also wanted to do fresh installation of Proxmox 8.2
My PC started as usual after adding new hardware. I went to factory settings to configure from beginning.

I was having an issue with Proxmox installation (this one) which was, from what I've read on forums, linked to the secure/legacy boot.

After a lot of restarts (more than 50 at least), after many switching between secure/legacy boot, I was close to resolve my first issue but after disabling secure boot once again, the PC started as usual but ports were no longer responsive. There was no signal across the DisplayPort, the keyboard wouldn't light up indicating that it was no longer connected or powered up. I have no other

I had similar issues with my main PC but I always managed to restore the BIOS. Not this time.

Here is a list of everything I've tried yet and I'm out of ideas/documentation :

• Unplugged power and pressed start button for 5/10/15/20 seconds then plugged again.
• Unplugged power, removed the BIOS battery, pressed start button a lot of times to drain the remaining electricity, tried powering with/without battery.
• Unplugged power, removed the BIOS battery for the entire night, pressed start button a lot of times to drain the remaining electricity, tried powering with/without battery.
• Pressed CMOS button (can be seen here) with/without battery when powered and not powered.
• Pressed CMOS button after playing with the PSWD (the green cover) moving it to the right/left pin or removing it entirely.
• Removing all RAM, trying with every singe one separately.
• Disconnected all disks from motherboard.
• Disonnected everything from motherboard leaving just the PSU (the motherboard was beeping because there was no CPU/RAM).
• Tried flashing the same BIOS version with the HP Utilities on USB Flash Drive and plugged it in the rear ports.
• Tried another power cable/DisplayPort/display.

I really am out of ideas, the PC is starting, the fans are spinning, I can hear the write from the HDDs but nothing more. The motherboard isn't making any sound as when the CPU/RAM were missing. At this point I don't see any other solution apart from buying a new motherboard.

Thank your for those who will read the entire post or help in any way.

 

[Ralston18]

Did you try replacing the CMOS battery?

Refer to the motherboard's User Guide/Manual regarding the proper procedures to clear CMOS and/or replace the CMOS battery.

 

[Semcraft]

I’ve tried with a brand new one. I tried the one from the motherboard into a remote controller and the battery was working.

From what I’ve found into various HP documentation, I tried removing the battery while unplugged, switched the PSWD cover and then plugged power and pressed the CMOS button according to what I’ve read but same problem.