Upgrade 3G to 3.1.3 and keep OLD baseband to unlock?

[keyztolope]

I currently have an unlocked 3G

firmware: 3.0.1
baseband: 4.26.08
bootloader: 06.04

Is there any way I can upgrade the firmware to 3.1.3 and keep the same baseband so I can unlock it again?

Thanks for any help!

edit:
I have a windows PC and a MAC
I also have access to an active ATT Sim card if needed

[madczech]

yes you can through pwnage (os x) or snowbreeze (windows) just dont do the official update through iTunes you will have to update with a custom fw

[keyztolope]

Ok thanks, where can I find this custom firmware? what is the most trusted site to dl this? thanks alot

[tatabox]

why do u want to upgrade to 3.13?

[TheWiredHavocMC2.0]

i could be wrong but 3.1.3 i believe has nothing in it but iPad stuff???
besides it will be more trouble then it is worth as 4.0 will be out soon enough

[madczech]

Ok thanks, where can I find this custom firmware? what is the most trusted site to dl this? thanks alot

you create your own custom fw through pwnage or snowbreeze

I would never download a custom fw...

[coolfella]

You can upgrade keepin the old baseband
use this link:
How to Jailbreak/Unlock 3.1.3 iPhone 3GS/3G/2G iPod Touch 2G/1G with sn0wbreeze Windows

[cheerfulsakib]

once we have jailbroken the iphone, are we able to access cydia to unlock?

I am not sure if just jailbreaking allows you to access cydia. Don't you also need to be on a valid sim card to access cydia??

[michal2648]

yes after jailbreaking you'll be able to access cydia and you do not need an att sim but like someone before said 3.1.3 doesn't really have anything new for the iphone just minor bug fixes you'd be better off and safer updating to 3.1.2!