Package: dpkg Version: 1.18.7 dpkg attempts to create a hardlink to the old versions before updating kernel files in /boot. In order to use `bootctl` without special options /boot is a FAT32 EFI partition that does not support hardlinks. This results in dpkg being unable to proceed.
$apt-get update ... dpkg: error processing archive /var/cache/apt/archives/linux-image-4.5.0-2-amd64_4.5.5-1_amd64.deb (--unpack): unable to make backup link of './boot/System.map-4.5.0-2-amd64' before installing new version: Operation not permitted dpkg-deb: error: subprocess paste was killed by signal (Broken pipe) Errors were encountered while processing: /var/cache/apt/archives/linux-image-4.5.0-2-amd64_4.5.5-1_amd64.deb E: Sub-process /usr/bin/dpkg returned an error code (1) Launchpad has a currently open copy of this bug <https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1318951> providing essentially the same information as I have. StackOverflow also has a reference to it <https://unix.stackexchange.com/questions/208073/dpkg-replacing-files-on-a-fat-filesystem>, with a suggested fix. Given that the `bootctl` expects /boot to be a FAT32 EFI partition and many guides are starting to recommend it, this bug will become even more prevalent as time goes on. I suggest dpkg use a fallback mechanism, like file renaming, when hard linking fails for file backups. Sincerely, Arthur Moore
