Prolly the downgrade. Have you tried the downgrade again with the hopes of no errors?
Saw this reg hack. If this doesn't turn it on, Weed's right with the hardware problem. Unless you can find a way to reload the BT stack drivers?
http://forum.ppcgeeks.com/showthread...h+stack&page=2 (last post)
btl1 is the device name for the Bluetooth radio. For more device information, see HKLM\Devices\Active.
Alternatively, power management for Bluetooth can be disabled completely using the following registry mod (NOTE: this may adversely affect your battery life):
[HKEY_LOCAL_MACHINE\Comm\Bluetooth device\Parms] "DisablePowerManagement"=dword:00000001