[SOLVED] is UEFI required?

dchmelik · 01-11-2024, 09:57 PM

My PC is set to classic BIOS mode but capable of UEFI... is this why booting Fedora GNU/Linux 39 crashes? I've been told contradicting things by different people (and maybe same will happen here) that in recent Fedora versions UEFI is or isn't required if the computer is capable.
        Don't ask me for log/report because as soon as someone on a Fedora Internet Relay Chat (IRC) channel told me UEFI is required, I erased Fedora and replaced it with RHEL GNU/Linux clone Rocky (CentOS) successor, though if UEFI wasn't the problem I'm willing to try Fedora again.
        Of course, I boot these RedHat variants from Slackware GNU/Linux's GRUB2 and noticed this doesn't work for Rocky, only when you use its own GRUB2 installation, so something may be similar for Fedora? Are there many configuration & kernel parameters other GNU/Linux may not be able to detect? I don't have this problem booting OpenSUSE, Debian/Devuan/Ubuntu/Neon/Mint, Gentoo, Arch, etc., all which don't have non-standard configuration that can't be detected.
        

GlennsPref · 01-12-2024, 12:54 AM

Hi, it's possible that the installer has changed the other drives/partitions uuid.. and now the slack grub has the old number (uuid).

The installer may also do a similar job on any other swap file space as well (if any other OS swap space).

As for UEFI... I dumped that and "signed" kernels as soon as I could figure out how. That's with secure-boot off, and CSM enabled. Make sure you set the individual drives to boot legacy, and not exclusive uefi.

OS Prober may not be installed automatically... check for the package and look at /etc/defualt/grub and make sure os-prober is uncommented and set to run.

/etc/defualt/grub

Code:

...
# discover other os's
GRUB_DISABLE_OS_PROBER=false
...

You can see you blockids to check the uuids... lsblk, blkid and your /etc/fstab

GlennsPref · 01-12-2024, 01:08 AM

There may also be configuration from the installer iso, when booted with uefi, the install will follow that flavour. So, you could check that too if you want to stay away from uefi.

here is a short note I copied from a devuan forum...

Code:

notes on bios uefi csm efi and such...

andre4freedom

If you set the motherboard to CSM mode, then you are well advised to install  in NON-UEFI mode!
If you set the motherboard to UEFI mode, then you MUST disable the "secure boot" option and install in UEFI (EFI) mode.
You can choose the install-mode  when you boot your stick afresh.
The Devuan installers handle these things quite well, usually... so is my experience with it.
I know, it's possible to fiddle with CSM disk mode and EFI boot, or in UEFI mode with classic (CSM) boot. If you succeed, all the better, but expect upgrades, migration or parallel-installs to fail.
I have learned that the hard way: EFI is fine, CSM is fine, but UEFI (secureboot) is a portal to hell.

.

I hope this helps, I know it used to confound me. :-) all the best.

dchmelik · 01-12-2024, 01:29 AM

Slackware has os-prober but it's possible if I updated Fedora in chroot then forgot to to run os-prober and grub-mkconfig this messed up Fedora booting. I doubt uuid was the problem (and I didn't run UEFI installer) but I'll check I did these things and see if I still have problem.