Iphone 3gs udgrade from 3.1.3 ro 4.x os?

[KushG]

Using 3gs on firmware 3.1.3 and Baseband 5.12 (New bootrom) JB by spirit n Unlocked by Ultrasnow. I wish to upgrade to 4.x os.
Can someone please tell me
1)Will i lose all data and apps
2) will I have to upgrade from I tunes then JB it? (Just like a New Restore)
3) Can i Use pwnage tool or some other to upgrade n JB at the same time

4) Which SW to use for JB and Unlock and which os to select 4.0, or 4.1 or 4.2 or 4.3(I will need an Unlock)
5)Will firmware upgrade also change BB version?

[Unregistered]

Using 3gs on firmware 3.1.3 and Baseband 5.12 (New bootrom) JB by spirit n Unlocked by Ultrasnow. I wish to upgrade to 4.x os.
Can someone please tell me
1)Will i lose all data and apps
2) will I have to upgrade from I tunes then JB it? (Just like a New Restore)
3) Can i Use pwnage tool or some other to upgrade n JB at the same time
4) Which SW to use for JB and Unlock and which os to select 4.0, or 4.1 or 4.2 or 4.3(I will need an Unlock)
5)Will firmware upgrade also change BB version?

1)Will i lose all data and apps

You need to back up your files , data and apps before upgrading your iPhone 3gs. OR else, you may lose it.

2) will I have to upgrade from I tunes then JB it? (Just like a New Restore)

Yeah, you can upgrade your iPhone, then jailbreak it .

3) Can i Use pwnage tool or some other to upgrade n JB at the same time

Please complete one task after another . don't do both the jailbreaking and upgrading at the same time . Sometime, it gets stucked during the process. If it persists, your total process gets in completed . So, firs upgrade your iPhone using pwnage tool and then jailbreak it .

4) Which SW to use for JB and Unlock and which os to select 4.0, or 4.1 or 4.2 or 4.3(I will need an Unlock)

Sometimes software may damage your iPhone after unlocking it . So, i would suggest you to use Remote unlocking method to unlock your iPhone 3gs from carrier lock . It doesn't requires jailbreaking . You can get it from any of the online vendors like ClassicUnlocking.com to unlock it . If you wish to use third-party apps, use cydia to jailbreak your iPhone .

5)Will firmware upgrade also change BB version?

Yes, the firmware is revised and is packaged inside the software update archive.