On Mon, Sep 18, 2023 at 11:39 AM John Jason Jordan <joh...@gmx.com> wrote: > > Xubuntu is on a three-year-old 1TB M.2 card and it has worked well for > years. I think I want to change to Debian, so I downloaded the Xfce > flavor of the Debian 12 ISO and burned it to a USB drive. Then I went > out and bought a new 2TB M.2 drive and installed it in the computer in > a spare, unused slot. I booted to the flash drive and went through the > installation, specifying the new 2TB drive, creating a 200GB partition > for / and 1800GB for /home. At the end the installer stopped and said > it had found the Xubuntu installation, and did I want to create a dual > boot? I answered 'yes,' and it said that upon booting I would have the > choice of which OS to boot to. After the installation completed and I > rebooted it went straight into Xubuntu; no option to boot to Debian, > like the new drive wasn't even installed. While in Xubuntu I noted that > the / and /home partitions on Debian had been mounted, so I looked at > them and all the files appeared to be in the partitions. > > The BIOS has a feature where you can choose which disk drive you want > to boot to; all you have to do is hold down F12 and you will get a > menu. I did so, and there was the new M.2 drive in the list, so I > selected it. Unfortunately it did not boot. Instead, a few minutes later > I was staring at a black screen with a flashing underscore in the upper > left corner. The keyboard was inactive, and there was no mouse. > > I had one more trick up my sleeve - go to the the BIOS directly. In the > BIOS I swapped the boot order of the drives so the new M.2 drive would > be first to boot. But when I booted it still wouldn't boot Debian; all I > got was the same black screen and flashing underscore. > > I've been reading up on how to get this to work and I haven't found the > answer yet. Both drives have a separate partitions for / and /home, and > each of them has a /boot/grub/grub.cfg file in the / partition. At the > top of the menu entries, the one in the Debian drive has Debian and > Debian-Alternative followed by 80 (believe it or not) menu entries for > Xubuntu. On the Xubuntu drive the file has menu entries only for > Xubuntu, although only about 20 of them. Methinks some serious tidying > up is overdue, but that can wait. Maybe a command to update grub is the > right way to do it. > > This would probably be easy to fix, if I only knew how. I'm anxiously > looking for suggestions so I can look at Debian 12 on the new drive. :)
I had a similar problem after I did an update yesterday. Only one of my systems was bootable. It turned out there was a line in the file /etc/default/grub like this GRUB_DISABLE_OS_PROBER=false which was commented out with a # in front of it. Uncommenting it then running update-grub fixed the problem. This however may not be your problem as there are many things that can cause this problem. Bill
