Upgrade Unlocked 3GS w/ 4.1 and 05.13.04 firmware

[kwinn]

Hi - I jailbroke/unlocked my iphone last summer using jailbreakme.com and ultrasn0w and it worked a trick. I really need some of the functionality and access to apps that will only work on 4.2x, but I can't figure out how to upgrade the software without upgrading the baseband. Help?

thanks so much!

 

[PsstGreek]

You'll need a custom firmware for 4.2.1 to upgrade, keeping your baseband.