The Beta Dashboard Microsoft released to members accepted into the System Update Preview Program is indeed flashing the firmware of some DVD drives (only fat/slim lite-on and fat BenQ afaik). The new beta dashboard, which has also been leaked online already, seems to be 13141/13142 for those who updated through LIVE and 13140 for those who got the green update disc. Besides flashing these drives with a new Original Firmware, it also has a new set of AP2.5 challenges.
Members who got accepted in the System Update Preview Program also received a XGD3 Halo Reach disc (a silver one for those who got the dash upgrade through LIVE and a green one of those who have to update with the disc).
The data reads larger than a DVD+R DL – but that may be faked / new protection so we will see.