Re: grub2 user interface disappears after upgrade from stretch to testing

Shane Dev composed on 2018-11-13 06:12 (UTC+0100):

> Thanks for your fast reply. From memory, I think the grub2 text menu
> installed by firmware-9.6.0-amd64-netinst.iso became a grub command line
> prompt after upgrading to testing.

> 1. For what possible reasons could have my grub menu disappeared?

You're using "testing". Bugs are to be expected at least on occasion. Sometimes
BIOS quirks interfere with Grub setup commands. UEFI BIOS writers probably do
not spend much time debugging their use with Linux and Grub. UEFI code still
has more maturing to do before consistency among different machines' behavior
can be expected.

> 2. You suggest I could boot Debian with "linux" and "initrd" commands. How
> could I determine which parameters to pass to these commands?

This is why I mentioned your backup grub.cfg file and provided a template from
one of my own systems.

The initrd line needs only the fullpath of the initrd to be loaded. The linux
line may work with no more than the same. Most cmdline options used in Grub
linux lines are options, meaning not necessary to a successful boot. The stanza
lines preceding the linux line may or may not be required. All you can do is
try, preferably based upon your backup. If you can't locate a backup, retrieve
the grub.cfg file via a rescue boot and work from it. Make use of tab completion
to get the appropriate names of kernel and initrd.