Originally Posted by safariking
Ey thanks but why can't we easy go back to a another rom?
Originally Posted by pseudoheld
but i am also curious why the "downgrade" process is so hard. i know from the razr that a few extra security checks have been implemented in 4.2 however it is still easily possible to go back to 4.1.2
First of all, you always have to do a factory reset when downgrading. Otherwise it may fail to boot because of force closes.
Android 4.2 is a bit more special. During the first boot everything on the external storage gets moved from /sdcard/ to /sdcard/0/. This is needed for the new multiuser feature (0 is the first user). When you go back to 4.1, the content is expected at /sdcard/. Since there is only the "0" folder, the standard folders (Music, Video, Download) will be created. Of course they are empty afterwards, while all the content is located in 0. The commands I listed above reverse the 4.1 to 4.2 data migration and put the files where 4.1 expects them.
On 4.1 the folder structure is the following:
On 4.2 it is
CWM has to be updated to find the backups at /data/media/0/clockworkmod. I'll post a new version soon. But this doesn't solve the downgrade issue.