Debian User Forums

Hi,

I have Debian 12 on one drive, Manjaro on another drive.

Both will boot if I get to the BIOS boot list and select either.

Debian doesn't stop (I'm guessing) at the grub screen to allow the choice of what to boot.

Manjaro does stop and I can select either fine.

For some reason the drive with Manjaro doesn't show up in the BIOS boot order setup. Otherwise, I just set the boot order to the Manjaro drive.

How do I get the Debian stop at the boot/grub screen to find out if it list Manjaro?

What have I done that make BIOS only see one drive as bootable.

It could be a BIOS setting, possibly related to how you installed Manjaro and Debian. Did you do one in EFI mode and the other in legacy/BIOS mode? If yes, you can't expect to see each in the other's Grub menu, but you may cause one to exist manually via an admin (you) composed stanza placed in /boot/grub/custom.cfg, or in /boot/grub./40_custom. In the long run, you may find it easier to reinstall one of the two in the other's installation mode. One way to tell if EFI mode was used would be to run the efibootmgr command. or command not found means you installed in legacy mode. Anything that looks like EFI boot data means EFI mode.

I'll take a shot here.
Boot into Debian (and Manjaro if needed) and edit "/etc/default/grub" file and add or modify the following (without info/notes in parentheses):

GRUB_DEFAULT=saved
GRUB_SAVEDEFAULT=true (makes auto selection be the last one booted)
GRUB_DISABLE_OS_PROBER=false (makes it look for other O/S)

Then do a "sudo update-grub"