Comment 1 for bug 1608290

It would be tempting to replace the existing "mount -o bind /dev /target/dev" in /var/lib/dpkg/info/rescue-mode.postinst with "mount -o rbind /dev /target/dev" instead, assuming that actually works. It should be possible to test that out by switching to tty2 a little before the rescue-mode component actually starts and editing that file in place with nano.