[gambatte]

If you read the "fine print" the BL reversion is prolly the only chance that you can really "brick" the phone (taken from that stcky):
NOTE: IT IS STILL VERY POSSIBLE TO BRICK YOUR DEVICE SO PROCEED WITH CAUTION. BOOTLOADER IS NOT THE SAME AS EXT_ROM, RADIO OR OS!!!!!!!!!!!
So if you had any errors, it could be a reason. But as alot of ppl have said, the radio is not selectively disabled. So that only your BT went out, has to be hardware.