iPhone Firmware 2.0.1 Downgrading

So the 2.0.1 upgrade can be pretty easily downgraded. “LostWhiteBoyy” has successfully done so and listed the report here. Note this is with a 3g device. Also, the modem on 2.0.0 is 1.45.00 and on 2.0.1 1.48.02. The modem baseband will not downgrade. But the device works anyway. This may, however, affect xSim type card operations. So if you are using one of those you should avoid the upgrade entirely. Also, it is unclear what the results are with a 2g downgrade. I may take one of my spare devices and test that.

“Just to confirm! you can downgrade back to 2.0! i upgraded from 2.0 jailbroken with winpwn to 2.0.1 (i noticed a difference in the text lag wasnt as bad). but i wasnt happy enough to loose my jailbreak so i downgraded all i did was is loaded winpwn then loaded the 2.0 firmware (i still had 2.01 on my iPhone 3G) and did all the steps and it worked no problem at all! ill wait to upgrade till the new firmware can be jailbroken!”

EDIT: When your baseband gets updated, the downgrade will be unable to flash the baseband. This may result in an error 1013, 1011, 1015 similar (101x). In this case, your downgrade has completed so all you need to do is boot the device out of recovery mode. Load up something like iLIberty+ and use its tools tab to boot the phone out of recovery mode and you are done.