Comment 10 for bug 1354730

FYI, for anyone that wants to use the original fix as a workaround until an official fix is released, the grub-installer script can be found at /usr/share/grub-installer/grub-installer on more recent versions of Ubuntu. So, step #3 given by TJ above becomes:

sed -i 's/\($chroot $ROOT grub-probe $@\)/\1 | head -1/' /usr/share/grub-installer/grub-installer

Changing this (I used nano to edit the file instead of sed) enabled me to install Ubuntu 14.04 LTS Desktop on a BTRFS raid setup without issue.