BIOS update, corrupted MBR and now no POST…help!

sp0okymuffin · 21 May 2021 at 19:37

Hey all,

First and foremost I lurked here a whole bunch back in January and thanks to all of your shared info and knowledge was able to build a really great SFF PC that has been serving me nicely… until today!

Spec:

Formd T1
Ryzen 5900x
ASUS TUF GeForce 3080
G.Skill Trident Z Neo 32GB
Asus ROG Strix X570-I
Corsair SF 750W
Sabrent Rocket 4.0 2TB NVMe

Machine was a dream then last night I decided to do some updates as Bluetooth wasn’t working. Installed latest windows update and grabbed BIOS from ASUS website. Upgraded, and machine would hang on boot.

Some Googling indicated this was likely corrupted MBR, and indeed I was able to (once) boot into Safe Mode and grab a Win10 ISO and burn to a USB for recovery.

After many attempts to rebuild the MBR (and constantly getting the “access is denied” error), I read that resetting BIOS to default might help, as well as disabling fast boot to get a verbose read of the boot process.

After disabling fast boot and saving and exiting the BIOS menu, now my machine won’t even POST! I get a black screen and eventually the machine switches off.

Any ideas for help?

All files backed up etc so if I need to reinstall Win10 no biggie, but I’d like to get something on my monitor at least!

Thanks!

Danny75 · 21 May 2021 at 19:49

Well, doesn't look like there's any BIOS Flashback on that board.

Drain power, take motherboard battery out for a good hour (it could take less but I've had a few times when I kept it shorter and nothing and I would have saved time just leaving it an hour lol). See if the board recovers its default BIOS.

Probably best to unplug the drive/s for now. Focus on recovering the board.

There's been a lot of Bluetooth issues recently and I found the update in Windows Optional Updates > Drivers. Try there if you get the board working again.

sp0okymuffin · 21 May 2021 at 21:27

Update: figured out display error – mobo had switched PCI back to Gen4 when cable was Gen3. Good thing I kept a Gen4 riser cable spare; was able to restore monitor display... now to try and fix my boot...

Danny75 · 21 May 2021 at 21:33

Nice. Good luck rebuilding MBR. Though if you end up needing a reinstall might as well switch to GPT unless you have a need for MBR. Backup everything you need.