Hi,

I've been given an iPhone that is running 3.1.3 and is already jailbroken and unlocked:

1. It has the new bootrom
2. baseband is 05.12.01

I am wondering if I have any reason to upgrade to a 4.x version. What will I 'get' from it?
If I want to, to which version? what method should I use? And are there any drawbacks (like having to upgrade the baseband)?

Cheers,
DB

upgrade to iOS 4.1
u can upgrade with Custom Firmware from PawngeTools which doesnt upgrade ur baseband
then just unlock with Ultrasn0w
dont upgrade to 4.2.1/4.1 Stock Firmware then ur baseband will be unhackable...
at the moment Pawengtools dont create Custom Firmware for 4.2.1 so 4.1 is ur best choice

What will be the gain from the upgrade? The features and app support of iOS 4?
Currently I have in Cydia a bunch of SHSHs - how do I back them up so that I can rollback in the future if need be?

I see that PwnageTool is only for Mac. Is that right?
Any options on windows or do I need a mac or mac image?

Cheers,
DB

Originally Posted by devboy

What will be the gain from the upgrade? The features and app support of iOS 4?
Currently I have in Cydia a bunch of SHSHs - how do I back them up so that I can rollback in the future if need be?

TinyUmbrella can backup a local copy of the SHSH blobs that are saved on Cydia.

As for the new features/improvements in iOS 4.x look at

Apple - iPhone - iOS 4 is the world as a starting point. Keep in mind some features are only available on the latest hardware (Facetime) others can be enabled via hacks for older models (HDR)

Originally Posted by devboy

I see that PwnageTool is only for Mac. Is that right?
Any options on windows or do I need a mac or mac image?

Pwnagetool is the only option. We don't recommend anything else. It is mac-only - so you need a mac or a virtual machine that runs OS X