Ok, new experiment. I'm including the steps here and in an attached README along with outputs captured at various points in the process in a tar.gz file.
I've moved drives around throughout this debugging process, but for this experiment they were; /dev/sda - 80GB spinner (os install drive) /dev/sdb - ZFS USB drive (problem drive) /dev/sdc - ext4 USB drive (data drive to transfer output files) Let me know if there are variations in the process I should try. miket$ cat README Auto Install up to "Install the GRUB boot loader on a hard disk" step Alt-F2 nano /target/usr/bin/os-prober (-ex) nano /bin/os-prober (-ex) ./step1 /target/usr/bin/os-prober > os-prober.log 2>&1 ps > ps.log cp /var/log/syslog . Alt-F1 Proceed with auto install of GRUB to /dev/sda Wait until it is stuck at 66% for about 1 minute Alt-F2 ./step2 ps > ps.log cp /var/log/syslog . ./step3 /target/usr/bin/os-prober > os-prober.log 2>&1 ps > ps.log cp /var/log/syslog . ** Attachment added: "experiment.tar.gz" https://bugs.launchpad.net/ubuntu/+source/os-prober/+bug/1770173/+attachment/5157000/+files/experiment.tar.gz -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1770173 Title: 18.04 install stuck on grub install To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/os-prober/+bug/1770173/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
