Debian 12 not booting, but OS intact
So I want to install Debian 12 on my machine, and the installer just -kind of- worked. I couldn't use the live USB with all the cool UI stuff, I had to use the normal installer without the whole DE. But that worked. I have Debian 12 now on my SSD. I can even access it through the "rescue mode" using the Debian USB as shown in the first picture. But actually booting from it is a whole other story. I can select it as a boot option, but it says that this drive doesn't have an operating system on it. It can be seen in the second picture.
https://lemmy.blahaj.zone/pictrs/image/45b0bbef-6d3b-42be-a15e-7ad1cf9485c4.jpeg
Has anyone an idea on what could be going on here?
UPDATE:
I got it working by messing around in the rescue mode. I selected some option which fiddles with the EFI boot and makes it accessible to the boot loader. So that's cool. Now everything works.
You should edit the post instead
It's the classic "Nevermind, I figured it out" right now lol.
Are you sure you installed the bootloader?
Classic "I wiped my ESP." Reinstall GRUB or whatever bootloader Debian uses from a chroot.
Looks like you need to configure your UEFI boot entry for Debian.
This might be fixable by reinstalling the bootloader. On boot the motherboard firmware is supposed to locate and execute the bootloader on the SSD. The error here looks like it's coming from the firmware having failed to do that for some reason.
Since you can get into rescue mode these instructions should work: https://wiki.debian.org/GrubEFIReinstall
That's always the first thing I try in this kind of situation.
Maybe there could be an issue with secure boot. But I'm not sure if that's something people need to worry about these days. https://wiki.debian.org/SecureBoot
There could be some sort of problem on the firmware side. HP has steps for troubleshooting this error here: https://support.hp.com/us-en/document/ish_3053911-2842957-16