Features:

Upgrades / Downgrades baseband to 4.26.08 for unlocking with the ultrasn0w tool released by the iPhone Dev-Team

UPGRADING:

Upgrading is for users that wish to remain on 2.2.1 but also unlock.  Upgrading will put the 4.26.08 baseband from 3.0 on the modem so that ultrasn0w may be installed from cydia

DOWNGRADING:

Downgrading works from any version greater than 4.26.08 (currently 5.08.01 is the newest version available, found in 3.1 beta 1).  It will put your baseband back at version 4.26.08 which is the current unlockable version by ultrasn0w.

Downgrading only works on phones that have the 05.08 (5.8) Bootloader from the factory.  This is a very limited number of phones that were released in the first few weeks of the 3G production cycle.

If you do not know your bootloader then you can run Fuzzyband and it will report the version number for you.

Any questions or comments can be directed to me fuzzyband@peacefulinsanity.com

Benefits over original downgrader:

• Does version checking, will only downgrade if phone is eligible
• Downgrades all versions of baseband from 2.30.03 to 4.26.08 (3.0 beta5)
• Reports current bootloader version on screen

The original downgrader was a possibly dangerous app, as it relied on a failed downgrade to decide whether downgrading was possible.  Anytime you run BBUpdaterExtreme you are potentially doing damage to the modem, so the version checking in this app minimizes the chances of accidently corrupting the baseband.

Questions, comments, and suggestions should be sent to w1kedZ or DHowett at fuzzyband@peacefulinsanity.com

Screenshots below:

In the news:
appleiphoneapps.com: Downgrade Baseband for Yellowsn0w