Comment 17 for bug 575469

Feature Freeze exception:
 - Adds a new feature to initramfs-tools and use it in grub2 to allow passing the "startup-event" flag to upstart. This is required to start friendly-recovery using upstart before any of the regular "on startup" jobs. Otherwise we'd have had to patch all the upstart jobs declaring "start on startup" or avoid using upstart entirely.
 - Add support for read-only and read/write recovery into friendly-recovery. Previous friendly-recovery would essentially start once most of the system services are already running and using read/write access to the FS.

UI Freeze Exception:
 - The recovery menu after this change is quite different. Instead of getting all the available options, the user is offered with only the subset that can run in read-only mode and an extra option to switch to read/write mode. Selecting that option then shows the usual set of options. I don't know if our documentation contains screenshot of the recovery mode, if it does, then these will need updating.