As anyone who frequently changes ROMs or customizes their Android device with flashable modifications will know, ClockworkMod recovery is one of the fundamental tools needed to do most things root or ROM related. It has plenty of features, and can do everything from installing a new ROM, to installing specific tweaks, to backing up your current ROM in its entirety.
Other than actually installing ROMS, backing up is probably one of the most useful features of ClockworkMod recovery. Nandroid backups are the standard fare, as they allow the user to save the exact state of their phone, complete with all settings and logins, to be restored for later use. However, developer Koush has just announced that he will be updating ClockworkMod recovery to support a new kind of backup, one that is almost a hybrid of baking up and making your own ROM, and that has the potential to be quite useful.
Instead of being the usual type of backup, which can only be restored through Nandroid, the new feature allows you to make your backup into a simple update.zip which can be flashed through any recovery. It does this by leaving out much of the data backed up by a Nandroid backup, and instead just includes the /system partition of your device. What this means is that “you can modify /system and boot/kernel to your liking, and just make a zip using this new feature…it doesn’t include /data and /cache. No personal data is stored in /system.” Basically, you will end up with a backup of your ROM, including new kernels and various mods system tweaks, but without any personal data or apps.
It isn’t quite like making your own ROM, but it is still a very neat feature. In particular, I think it could be useful for reinstalling a fresh, app free version of your ROM without having to go through the hassle of reinstalling all of your recovery-level tweaks. With a .zip backup, you get a lot less of the clutter but retain the customized ROM base, and have a nice personalized firmware that you can build on yourself or even distribute to friends. The feature isn’t out just yet, but should be going live in the next build of ClockworkMod recovery in the coming days, when I’ll be sure to give it a try.[xda-developers]