I have an Acer Aspire 5 where I removed the existing hard drive partitions and installed two LUKS-encrypted instances of Ubuntu 20.04.2. (There is no Windows operating system or recovery disk anymore.) I can access the F12 boot menu to select what to boot, and I can boot into my Ubuntu installations. But the F2 button to enter the BIOS setup no longer works -- it just makes the computer hang on the Acer logo screen.
(1) Does anyone know what might cause this problem and how to fix it?
(2) Would removing the CMOS battery and putting it back in help, and does anyone know if this type of action typically voids warranties on computers?
(3) If I can't get into BIOS setup but the computer otherwise seems to be working, is there any reason I need to worry and try to still fix this problem right away?
Here are some more details if it is helpful:
After installing one encrypted instance of Ubuntu, I made a mistake and renamed the EFI/ubuntu folder on the EFI System Partition (instead of the correct way of using grub-install to create different boot entries with different id's, which I did later). This meant that the computer couldn't boot successfully. At this point (and when I added a second Ubuntu install), when I went into BIOS using F2, the boot order there started acting strange; for example, sometimes there would be just a blank entry, and other times an entry would show for the hard drive and a second blank entry would show. One time I watched as the name of the entry had some gibberish string that changed once while I was navigating on the screen. I could still access BIOS using F2, except for when I had an external DVD drive plugged in -- then F2 would cause the computer to hang on the Acer logo screen. But when I accessed BIOS to try to select the option to reset the BIOS settings to default, put the external DVD drive at the top of the boot order, etc. I ran into problems of unexpected behavior, the computer freezing, etc.
To fix this problem of the computer not booting, I stumbled into the grub command line, I think from some attempt to boot from a Live Ubuntu DVD which didn't actually boot successfully but just took me to the command line. I was able to unlock an encrypted boot partition for Ubuntu, specify the kernel and root filesystem, set the initrd file, and boot. From there I was able to get the computer fixed so it would boot successfully in the future again without using the grub command line. I then installed a second encrypted Ubuntu.
When BIOS was still working, I added a supervisor password, I disabled both Secure Boot and Fast Boot, and I eventually enabled the F12 Boot Menu. There was no way to move out of UEFI mode into a legacy BIOS mode.
After installing the second Ubuntu instance, I don't remember if I tried accessing BIOS with F2 right away. The next day I realized I could no longer get into BIOS however; the system just hangs at the Acer logo screen.
If it helps, currently in the EFI System Partition there are four folders: BOOT, ubuntu, Ubuntu1, and Ubuntu2. I think BOOT already existed; ubuntu and Ubuntu1 both load the same encrypted Ubuntu install; Ubuntu2 loads a second encrypted Ubuntu install. (Because of how grub creates boot entries, the "ubuntu" entry gets created even though I don't actively use it.) Each Ubuntu install has an encrypted boot partition and a second encrypted partition which includes the filesystem (/) and swap. Each Ubuntu install also has an unused grub partition. The Ubuntu1 and Ubuntu2 entries were created using grub-install --bootloader-id=Ubuntu[X] --no-uefi-secure-boot (the last flag prevented an issue where ubuntu/grub.cfg would be used even when the Ubuntu1 and Ubuntu2 boot entries were being used). efibootmgr successfully shows entries for the ubuntu, Ubuntu1, and Ubuntu2 folders along with "EFI USB Device", "EFI DVD/CDROM", and "EFI Network", and I can use efibootmgr to rearrange the boot order, delete entries, etc.
Thank you!
