Originally Posted by Europa
I unlocked my 3G with Pwnage Tool and ultrasn0w and have crazy battery drain on T-Mobile. I also have a 3GS with AT&T, so unlocking the 3G was just a test to see how well it works. Basically, I have to leave it in Airplane mode and just take it out to make calls unless I want the battery to drain to nothing in less than a day in standby mode. I've tested it with WiFi, location services, etc off and isolated that the battery drain problem is the unlock itself. I'm getting five bars on T-Mobile, so I don't think the problem is that it's constantly searching for a signal.
The battery life problem on my unlocked 3GS seems to be resolved. The battery life is really good now and I don't have to leave it in airplane mode anymore. I didn't restore the phone, so I'm thinking a Cydia update fixed it.