I was lucky enough I guess to have another PC handy and swapped my Q8300 that didn't work for a Q8200 which worked. But I agree I think this issue probably can and should be addressed by Intel with a BIOS update? Is anyone at Intel listening? At the very least (but it will be no help to people like xxeyes) fix the compatibility table.
Same problem with a DG33FB and a Q9550s ... Motherboard worked very fine with a Q6600 but is unable to identify my Q9550s so can't use VT-x and other things very usefull. Waiting for BIOS update but ...
Impossible to flas in previous version
Flash with same version with iso = Idem
Clear CMOS and flash in recovery mode = OK
My CPU is now well known.