iPhone upgrade iphone 3g 3.1.2 to any better ios.. need help

[roshaan]

hi. i am a newbie to iphone. i request some guidence

i have an old iphone 3g jailbroken with ios 3.1.2.
i want to upgrade the ios to a newer version. please suggest me an ios for this phone which i can jailbreak. advice from an experienced user please

 

[TriJetHero]

4.2.1 which is still signed by apple, it also the highest you can go on a 3G.

for the jailbreak
http://www.iclarified.com/entry/index.php?enid=12947

 

[roshaan]

Trijet would it be too much to ask if you guide me through the process, coz i really m not a computer wiz and dont know much of the terms used here.. ure help will be truely appreciated..

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"If your baseband is already unlockable and you are on a lower firmware version then use PwnageTool to update to 4.2.1 without upgrading your baseband."

do i come in this category?? it is copied from the link u pasted.. and should i follow the instructions given?
i have important notes on my iphone, would it be cleared too if i upgraded it?

 

[dhlizard]

4.2.1 which is still signed by apple, it also the highest you can go on a 3G.

for the jailbreak
http://www.iclarified.com/entry/index.php?enid=12947

Edit: Correction - this is 3G not, 3GS, my original reply was inaccurate

 

[TriJetHero]

yes that would be a bit too much…

Do you need to unlock the phone?

 

[roshaan]

my phone is unlocked already, i mean jailbroken on 3.1.2.. i just want to update to a newer version of ios.. my cydia isnt working on this one, it crashes on loading, so i thot upgrading to a newer version would solve the problem..

 

[TriJetHero]

try reading up first on jailbreaking and unlocking, 2 different things.

 

[roshaan]

yea my phone is jailbroken plus unlocked, it can be used with any carrier.. i m just wondering, would it hurt to upgrade from ios 3.1.2 to 4.2.1? coz there r quite a few apps etc which only support's ios4 or above.. and how should i save my data before upgrading to the new ios. please help

 

[TriJetHero]

is it factory unlocked, IMEI unlocked or software unlocked? it makes a difference.

Txt, contacts, pic etc backup via itunes, jailbreak apps via a 3rd party backup from cydia or manual after rejailbreak.

 

[roshaan]

i dont know about if its factory unlocked or IMEI or via software.. how can i find out? i bought it from someone a year ago in this condition as it is now, jailbroken and unlocked.. oh yea, after restore and jailbreak, do i need to unlock again?

and contacts, notes and pics etc i can backup on itunes? like i should back up the fone before upgrading to new ios and then sync it with itunes would bring my stuff back, right?