A new tweak has been released in Cydia, called "Fake About Screen". It allows you to set whatever firmware, capacity, serial number, etc, that you want, making your jailbroken iPhone and iPod touch look like a future version of the Apple device.
It wont be long before some newer apps from the iTunes App Store will require you to have the latest iPhone 3.1.3 firmware in order to install a particular app. Earlier this month, Apple released the new iPhone OS 3.1.3 for iPhone and iPod touch which upgraded the baseband to 05.12.01 for iPhone 3G and iPhone 3GS, hence making it impossible to unlock them on the latest firmware with the newer baseband.
