I bought a 3rd party battery off ebay and it worked great with 2.1, I installed the new version just now and it does not recognize my battery. I tried to reboot and now the phone wont come up at all (shows the battery with a ? on it)... HELP!
Looks like you cannot use the 2.1 SBF to flash the Froyo official OTA release. You will be bricking your phone.
I would do some research first.