GTX 970 no post, black screen, no signal, after accidentally activating something in UEFI

[CanidConqueror]

Hello everyone!

First off, thanks for taking the time to read this. I'm a little out of my league here.

Here's my hardware:

MSI MAG B550 Tomahawk AMD B550 So.AM4 Dual Channel DDR4 ATX (not sure which firmware, but I got it in January and updated it then)
AMD Ryzen 5 5600X 6x 3.70GHz
850 Watt Corsair RMx White Series RM850x Modular 80+ Gold
2x Crucial Ballistix BL16G36C16U4B.M16FE1 16GB DDR4-3600
Asus STRIX GTX 970 4GB
1TB Samsung 970 Evo Plus M.2 220 PCIe 3.0 x4 NVMe (MZ-V7S1T0BW)
Some old 7200RPM HDD for storage
Some old SanDisk SSD Plus 240GB


In order to install Manjaro on my old SSD, I went into my UEFI settings and disabled Secure Boot, as well as CSM ("UEFI only" I believe was the other option). Later on, I wanted to change something else in the UEFI,  but for some reason after the Manjaro installation, the resolution was extremely low to the point of it being mostly unreadable. I know I'm stupid, but I tried anyway, but it appears I accidentally chose the wrong option. I wanted to back out, but accidentally confirmed instead. I THINK I did something regarding GOP, Secure Boot and UEFI, but I don't know what exactly. Right after, the entire PC just froze up, and the only option was a hard reset. Ever since, my PC won't post anymore and the screen stays black (both monitors say they're not getting any signal). CPU fan, front fan and PSU fan are turning. GPU fan is not, but never did during boot-up. The keyboard will light up on Num, Caps and Scroll, and a few seconds later, only Num stays illuminated. SOMETIMES the EZ Debug LEDs will light up red after hitting the power button, one after the other, and go out again. SOMETIMES the "BOOT" LED will stay red.

Here's what I've already tried:

• I've read and done all the sensible things in this thread:

 

• Tried to reset CMOS (through battery removal, as well as using the jumper method) many times, to no avail
• I've taken off all hard drives and SSDs, tried to boot with only one RAM stick in
• I have plugged in my Manjaro SSD and my GPU into an old computer, confirming that both are working (computer won't boot into the SSD's OS because the boot loader I think was on the nvme, but I can mount and use it in a live USB environment)
• Tried GPU in other PCI-e slot
• Tried both DVI slots and the HDMI slot, and different monitors

Sadly I can't test the rest of the hardware in my old machine since they're not compatible.

Is it possible that I accidentally activated GOP, and my GTX 970's BIOS isn't up to date and doesn't work with it? if so, would flashing a newer, compatible BIOS fix my issue so I can reset the UEFI?
Did I somehow short my board and now my PCI-e lanes are fried?
Or did a short somehow kill my power supply, not giving enough power to the GPU?
Or is it really just the UEFI?


Thanks for reading. Please let me know if any additional information is needed. I've been up all night with this.

[CanidConqueror]

I have now completely reassembled the PC (was thinking, maybe reseating the CPU miraculously does something), but that didn't help either. Not that I expected it to - the problem appeared in a system that was previously running completely fine after all. 

 

Really getting desperate here. 

[CanidConqueror]

No one got a clue?

[CanidConqueror]

Since I've exhausted all my options and no one seems to be able to help, I'm gonna try to completely flash the BIOS using the Flash BIOS button (can't use other methods since I'm not getting any signal from my GPU). 

 

Since I can't get any visual feedback and I don't wanna brick my motherboard (if it isn't already) - how long does this process usually take? Should I power it down after a while, or will it do it by itself? 

Edit: Apparently a light is gonna flash during the process, and it's gonna stop once it's done, according to Youtube.

[CanidConqueror]

I fixed it myself. The BIOS flash actually fixed all my issues. I was hoping to fix it without it, also because it would be a great learning experience. But oh well. At least I had some fun disassembling and reassembling two different systems, and installing and using Manjaro on the older system for a while. It's now my media PC in the bedroom.

What I did:

• You only need your PSU, your motherboard and a USB stick for this - but you don't need to remove any components if they're already in the machine
• Downloaded the latest BIOS for my motherboard (MSI MAG B550 Tomahawk)
• Formatted a 16GB USB Stick to FAT32
• Unpacked the downloaded file, and renamed it to MSI.ROM (make sure to watch the file type!)
• Put it in the back  (of the motherboard - dedicated USB slot on the top of the board, marked by a white rectangle around it, near the FLASH BIOS button)
• With the PC off, I used a screwdriver to press the FLASH BIOS button.
• A light will flash around the button, as well as on your motherboard. Wait for the light on the button to go out.
• Upon restart, the BIOS is completely reset (since it's a fresh install), and everything should work fine again. At least it does for me! :]