Undo Android 4.0 (aka Ice Cream Sandwich) Full Disk Encryption Just upgraded my Nexus S to Android 4 aka Ice Cream Sandwich. Was looking through all the new features, and decided to enable encryption, which worked (and is working) just fine. Now I'm wondering if I can undo that and revert to an un-encrypted filesystem.

There does not seem to be an option in the settings area, and while I'm not fussed about doing a factory reset, I just wonder if I'm missing an obvious option somewhere. Can anyone help? Or even confirm that the factory reset is the only way out?
There should have been a warning when you begin the encryption that you had to agree to. The only way to unencrypt it is to perform a factory reset, thereby wiping your data partition completely.