flash radio in HBOOT, but instead of rebooting, pull battery, then hold vol down and power to boot into recovery and flash your backup.
i think you mean flash the backup in recovery,then pull the battery and power on/vol - into hboot,then flash the radio(this is how we did it from from froyo to GB).
if you flash the radio in hboot,pull the batter,and power on/vol -,youll just enter hboot again,and i do not think there is an option to go to recovery if you choose no to update,only to reboot the phone.
seems ska.t73 and i determined this in another thread. youll have to get the PG05IMG file off the sd card before you can get to reccovery via hboot without updating.
if i remember correctly,you could:
-move PG05IMG file to sd card
-power off
-go to hboot and flash radio(power on/vol -)
-yes to update
-chose no to reboot after update
then i think it will let you go to recovery
-restore froyo backup
i dont need to flash anything in hboot right now,but i may go back to cm7 tonight or tomorow. if i do,i will double check and see if that works since ill need to flash back the stock radio
at any rate,i do not believe it will be a big deal to flash the radio first,instead of second,as recomended in the original GB RUU thread. i saw a couple of instances in the ruu thread where people restored a backup and booted it with the GB radio. only thing that happened was the phone didnt work
but going back and flashing the froyo radio after the fact fixed things with no apparent prollems.