En el foro de XDA he encontrado esto sobre si hacer wipe o no:
Originally Posted by big_killer
only a bit curious.. in order to upgrade from rc 3.1 to rc 4.1
Is it recommended to factory reset and wipe caches?? cause on the first page it only says to flash in cwm??
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Just flash in CWM. The script checks if a wipe is needed and proceeds accordingly.
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Lo acabo de actualizar en el mio del 3.1 a la 4.1 sin wipe y de momento ha ido bien sin complicaciones.
Saludos.