Seeing the same problem here. Perhaps the key is /boot being on a separate device with / on LVM volume?
# df Filesystem 1K-blocks Used Available Use% Mounted on /dev/dm-0 16513960 3697920 11977184 24% / tmpfs 126924 0 126924 0% /lib/init/rw udev 121888 164 121724 1% /dev tmpfs 126924 0 126924 0% /dev/shm ... /dev/sda3 264443 48629 202159 20% /boot # apt-show-versions | grep grub grub/testing uptodate 0.97-61 grub-common/testing uptodate 1.98-1 grub-doc/testing uptodate 0.97-61 grub-legacy-doc/testing uptodate 0.97-61 grub-pc/testing uptodate 1.98-1 # update-grub /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?). # apt-get --reinstall install memtest86+ Reading package lists... Done Building dependency tree Reading state information... Done Suggested packages: hwtools memtester kernel-patch-badram memtest86 The following packages will be upgraded: memtest86+ 1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. 1 not fully installed or removed. Need to get 0B/152kB of archives. After this operation, 4,096B of additional disk space will be used. Reading changelogs... Done Preconfiguring packages ... Selecting previously deselected package memtest86+. (Reading database ... 83347 files and directories currently installed.) Preparing to replace memtest86+ 4.00-2.2 (using .../memtest86+_4.00-2.3_i386.deb) ... Unpacking replacement memtest86+ ... /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?). dpkg: warning: subprocess old post-removal script returned error exit status 1 dpkg - trying script from the new package instead ... /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?). dpkg: error processing /var/cache/apt/archives/memtest86+_4.00-2.3_i386.deb (--unpack): subprocess new post-removal script returned error exit status 1 /usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?). dpkg: error while cleaning up: subprocess new post-removal script returned error exit status 1 Processing triggers for man-db ... Errors were encountered while processing: /var/cache/apt/archives/memtest86+_4.00-2.3_i386.deb [ Rootkit Hunter version 1.3.6 ] File updated: searched for 164 files, found 139 E: Sub-process /usr/bin/dpkg returned an error code (1) -- Ned Deily n...@acm.org -- [] -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org