Full Clean Wipe

When upgrading Android devices from one ROM to another ROM, or from one version to another (e.g. Ice Cream Sandwich to Jelly Bean), it's best to do a full wipe. Me, I always do a full wipe just the same to be sure that the new ROM works well with no artifacts from the previous ROM.

For of all, do a backup from the recovery. Obviously, make sure you have enough disk space (and battery power) to complete the operation.

1. Under Mount & format, do a format system.
2. Then format data.
3. Then format cache.
4. Go back to the main menu, then wipe data/restore.
5. Then wipe cache partition.
6. Go to Advanced, then wipe Dalvik cache.
7. At this stage, you can proceed to flash your new ROM.
8. Reboot, then proceed to flash gapps and other zips you want.
9. Reboot again.