Originally Posted by derricancy
Oh, really? Thanks for reminding me....now I know it..
If you do a nandroid backup it doesn't backup hboot.
So if you are on GB and do a backup hboot will not be copied.
Then if you decide to flash ICS you have to flash new firmware also, an hboot with higher version number, for instance 1.27.
If you have hboot 1.27 and try to restore GB backup it will bootloop.
You first have to flash a lower number hboot, for instance 1.17.
If you do that there will be no problem.
The procedure is: first flash back the same hboot you had when you were on GB, then you restore the backup.
The reverse is also true of course. If you want to restore ICS backup, first flash same firmware you had when you made the backup, then restore it.
I also always make sure to use the same recovery software and version when restoring to minimize the likelyhood of errors.