Edit: Further research reveals the BIOS flash probably was actually OK and went exactly as HP intended, and broke compatibility with my Samsung SSD! See my reply in the comments...

Just thought I'd share a bit of a nightmare I've had recently updating the BIOS on a HP 280 G2 MT desktop (Long story, TL;DR at bottom)...

I've only just bought it, second hand admittedly, I was (and still am) having trouble with the VGA output to my TV and I was thinking maybe a BIOS update would fix it (I've updated all drivers etc.). So, I downloaded the latest BIOS from HP and installed it from within Windows as per normal, everything appeared to go fine, the machine restarted automatically but then just hung at the HP logo POST screen, and this is all it would do.

Not a problem I thought, this is a modern machine so it'll be easy to recover a failed flash, right? Wrong... I looked up the procedure; make a recovery USB pen (on a working PC), plug it into the failed PC and hold down the Windows key + B and power up pressing the power button for 1-3 seconds... I tried this several times and it simply did not work, it'd just boot to the HP logo POST screen & hang. I tried clearing CMOS etc., nothing made any difference.

Then I spotted a jumper position on the motherboard marked 'BB_REC' right next to the clear CMOS jumpers, this got me wondering whether it was a BIOS recovery jumper. I checked manuals but found no mention of this jumper, however I thought what harm can it do, the board is potentially knackered now anyway! So, I removed the jumper from the clear CMOS position and placed it onto the BB_REC position, then booted the PC as per procedure above and bingo, eight beeps and my USB stick started flashing away and the BIOS recovery screen appeared! I breathed a sigh of relief and thought I'd sorted it. But, it was not to be, the machine went through the procedure of flashing the BIOS but at the end it all said 'verification failed'. The machine rebooted anyway and now a different screen appeared, a few lines of text with the system information and BIOS version (Version A0.50 which was the one on the recovery stick). However, the machine still just hung here and would not respond to key presses or boot any further.

So I tried the recovery procedure again and exactly the same thing happened, verification failure. So, I thought I'd try recovering to an older BIOS version, so I made a recovery USB stick with the older version available, A.27, but this stick would not boot into the the recovery mode, the system tried to read it but would not boot from it.

Next thing to try... Take the A0.50 recovery stick, delete all BIOS images from it and replace them with the older A0.27 images. Tried this and bingo! It installed and the machine restarted and said 'no boot devices available', even though my SSD was still attached and had Windows installed? A quick reinstall of Windows 10 though and the machine is now fully functional! Yey!

Conclusion:

All in all I think I've spent the best part of 4-5 hours on this and I would probably have been better off just buying a new motherboard (this one is standard ATX)! I'm wondering if the windows key + B method even works on this system? Or does it only need the BB_REC jumper fitting? Why is there no mention of this jumper in any HP documentation?!

Extra details:

1: I had to clear CMOS before attempting to boot from the recovery stick every single time or else the system would not try to boot from the recovery stick, even doing this didn't always result in the machine booting from the recovery stick, sometimes taking 5-10 cycles of this to get the machine to boot the recovery stick!

2: I had to remove the BB-REC jumper once the BIOS recovery screen appeared or it didn't seem to flash properly, taking a very long time to write but seemingly not actually writing.

3: Once a recovery flash attempt had been performed from a recovery stick, the stick would not boot again and the stick had to be re-made!

4: I still don't know the exact procedure that worked! As you can see above I had to try many things and I'm still not sure exactly what made the final recovery flash work.

5: Picture of the mystery jumper here: https://i.imgur.com/wXDZaxE.jpg

TL;DR

BIOS flash failed, no HP written procedure worked to enter recovery. Found mystery jumper on motherboard which allowed me to enter BIOS recovery but latest BIOS didn't work & older BIOS would not boot, had to put old BIOS files on newer BIOS recovery stick, all this took waaaay too much time.

TL;DR #2

BIOS flash went bad. Fix was complicated.