Comment 23 for bug 1621507

initramfs-tools has been reverted in xenial due to regression (bug #1631474). Resetting the bug state, we need to get support for ipv6 back into xenial-updates but in a regression-free way, which - per discussion on bug #1631474 and bug #1634176 - probably implies a separate 'ip6=' boot option, with corresponding changes to the components populating the boot commandline.