On Sat, 6 May 2017 18:12:03 +0200 Pascal Hambourg <pas...@plouf.fr.eu.org> wrote:
> Le 06/05/2017 à 17:19, Joe a écrit : > >> > >> However, the ls command I suggested may still be useful to check > >> GRUB's idea of the sizes. > > > > ls (hd0) > > (hd0): Filesystem is unknown. > > > > ls (hd0,1) > > (hd0,1): Filesystem is ext2. (after several seconds' pause) > > > > I'm only getting the grub rescue> prompt, not the grub> prompt. > > I expected that "ls" would be the same in normal and rescue mode. > Obviously I was wrong. > > If the GRUB version on the internal disk is the same, you could boot > from it while the USB disk is connected, and if the BIOS exposes the > USB disk even though it is not the boot disk (some BIOS do, others > don't), then you could use the "ls" command in normal mode to check > (hd1) and (hd1,1). Yes, that works, and looks right: Device hd1: No known filesystem detected - Sector size 512B - Total size 117220824KiB Partition hd1,1: Filesystem type ext* - (Last mod time, UUID) Partition start at 1024KiB - Total size 10485760KiB However, (still from the host machine's grub): grub> ls (hd1,1)/boot < reasonable listing > grub> set root=(hd1,1) grub> linux /boot/vmlinuz-4.6.0-1-686-pae root=/dev/sdb1 gets me: error: "attempt to read or write outside of disk 'hd1'." This result, from a second grub installation, suggests a broken filesystem, despite the partition being readable and writeable when mounted. I had already copied /etc from the drive, and was trying one last attempt to boot to obtain a dpkg --get-selections in preparation for a reinstall. A quick fsck /dev/sdb1 from the host confirms this, and a couple of fsck -y runs (what have I to lose?) gets it booting again. So --get-selections saved, and now to try the long-delayed dist-upgrade... Thanks again. -- Joe