This is more than likely my fault for messing with UEFI in the first place.
tl;dr: I can't boot my Samsung RV520, the boot order is set in the BIOS/UEFI and I can neither boot from USB or DVD. What can I do?
I decided to upgrade from Ubuntu 18.04 to Ubuntu 20.04. After the installation my laptop would boot to the boot device selection screen and the wrong boot device was highlighted, so I wanted to change that. I couldn't in the BIOS (after a reboot the old boot order was back), so I decided to use efibootmgr.
I ran sudo efibootmgr -o A,B,C, which was "grub", "ubuntu" and "Windows Boot Manager".
This is now the fixed boot order in BIOS. It doesn't boot anything though, but just boot loops. I can still enter the BIOS, but new boot devices don't appear (USB or DVD) and changing the boot order doesn't do anything.
I also can't get to the Boot Menu to select a new boot device on the fly. I tried all the F keys, but the boot menu doesn't show.
- F2: starts the BIOS (works)
- F4: should start the recovery, but I removed that partition years ago.
- F8/12: one of them should show the boot menu, but they don't.
- F9: If a HDD is connected to laptop it turns off. If no HDD is connected the screen turns black (loop stops) and the CPU Fan starts spinning up.
I removed the BIOS battery over night, which did reset the BIOS, but the boot order persists.
It's a Samsung RV520 running a Phoenix SecureCore Tiano-BIOS. The HDD is GPT formatted and the uefi-partition is sda1 (ubuntu / is sda4).
1 Answer
So I got this fixed luckily. In short: I was able to boot by using an undocumented function of my bios which was that F3 always tries to boot from DVD. Using this I was able to boot WinPE and from there I was able to reset my bios.
The procedure is described in detail here. It also describes (in the links) how to obtain the necessary files.
Thanks to the people at notebookreview.com!
