Comment 56 for bug 1274320

Sadly post #34 did not work for me - server 12.04 clean install using LVM on small system disk; intending to use ZFS on further 4 disks.
Staggering up the Linux learning curve; used vi to modify 00_header, and having found the 2 existing lines:

function recordfail {
  set recordfail=1

assumed that the first two lines of the fix:

if [ "$quickboot" = 1 ]; then
    cat <<EOF

should precede these 'recordfail' lines and the remainder of the fix follow them.
I then ran update-grub and saw what I take to be an error message about grub-probe (the suggestion to type grub-probe - help didn't help) and the diskfilter writes message came up at the next reboot.
Was that a false assumption? - what else might have happened - was pretty careful to avoid typos?
Thanks.