Hi,
Had a simular problem a while ago, cold boot issue, but it turned out to be a graphic card fault,

Also
check Did You load optimized defaults then save and apply and reboot
I believe on all new GA bios's cold booting was fixed ,
so likely you just did not do the load optimized and save and apply/reboot the last time you flashed.
I know you have the newest bios, but without loading optimized, and then reset you can get a problem,
Also Check your cmos battery
Just my two penneth!