Comment 3 for bug 748340

Semi-rectraction of previous statement:
Turns out the reason it was booting was simply that it was failing due to the extra "-a" flag and skipping the fsck entirely.

I did not manage to apply the latest ubuntu change to the debian experimental version (and I know to little to resolve the merge there I think)

However, Simply grabbing the btrfsck binary from debian experimental and running it alongside the ubuntu version on the latest liveCD, the ubuntu one fails with the error above, whereas the debian exp succeeds to run the fsck.