New updates have been released for all of the Ubuntu and Debian AMIs listed on:
The primary enhancement in this release is an emergency correction for a defect in the previous AMIs, to wit: The /etc/fstab file was missing and /mnt was not mounted as ephemeral storage.
Thanks to Garrett Smith and Ken Lim for identifying and reporting this problem. I had apparently missed the notice that the latest ec2- bundle-vol from Amazon requires —generate-fstab if you want to have an /etc/fstab when creating an AMI from scratch :-\
The defective AMIs are hereby deprecated and may eventually be withdrawn.