Flashing PR1.2 over PR1.3 is possible
 

Don't get me wrong, PR1.3 is great!

Just let you know: Flashing PR1.2 over PR1.3 is possible.
At least these are working after 'downgrading':
WLAN
GSM
Camera

(My point: I have read that flashing PR1.1 over PR1.2 was not possible, because of gsm firmware update.)