After booting into the system manually from the GRUB prompt, setting "GRUB_DISABLE_OS_PROBER=true" in /etc/defaults/grub and rerunning update-grub was enough to get the system booting again on its own.
It turned out the "root" partition OS prober was choosing wasn't an old one at all, but the "/usr" partition for the current installation (I'd missed that initially, because I set up this system a couple of years ago and had forgotten how the partitions were mapped). -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/551790 Title: lucid update-grub wrong root=UUID= -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
