i just checked iclarified and the dev team has posted 'how to jailbreak iphone 3G on OS 3.1.2'.
iClarified - iPhone - How to Jailbreak Your iPhone 3G on OS 3.1.2 Using PwnageTool (Mac)

however, the instruction is for jailbreak and NOT for unlocking 3.1.2, so am i missing something here because they have jailbreak and unlock available for 2G OS 3.12.

i have unlocked and jailbroken my 3G with OS 3.0, so if i upgraded to OS 3.1.2, does it mean my phone will be locked and i will have to wait for the dev team to release the unlock piece for it?
Edit/Delete Message

If you upgrade a 3G or 3GS iPhone to official apple iPhone OS 3.1 or 3.1.2 you will lose software unlock.

There is a real possibility that the dev team will not ever be able to unlock the baseband included in these two OS updates.

The dev team's recommendation is to make a custom IPSW using pwnagetool and upgrade using that. This custom firmware disables baseband update. So you end up running 3.1 or 3.1.2 with the baseband from 3.0. Then the unlock from 3.0 can still be used and you have access to the new features and bug fixes from 3.1 and 3.1.2

Once you have loaded a custom IPSW you should be very careful never to load an official IPSW (OS update) from Apple as this will relock you phone with the new baseband that cannot be unlocked.

hi there,

thank you very much for your quick reply. what you said makes sense, but i am not sure i understand how to make the custom ISPW for 3.1.2

when i jailbreak and unlock OS 3.0 with baseband 04.26.08, this is what i did
1. created the custom ISPW running pwnageTool_3.0.app and iPhone1,2_3.0_7A341_Restore.ipsw
2. then i use ultrasnow to unlock

my questions for OS 3.1.2 ...
1. don't i need to upgrade 3.0 to 3.1.2 from itunes, then
2. then create custom ISPW for 3.1.2 using
. pwnagetool_3.14
. iPhone1,2_3.1.2_7D11_Restore.ipsw

HOW DO I UNLOCK it after jailbreak? do i still use ultrasnow? is ultrsnow able to unlock 3.0, 3.1, 3.1.2??? according to iclarified site, for ultrasnow you must be running 3.0 firmware with baseband 04.26.08, it does not say anything about firmware 3.1 or 3.1.2. so i am not sure which app to use to unlock 3.1.2 (i am using Mac)

thanks!!

Just check the source: DEV-TEAM BLOG

__________________
** If you just want to support hackint0sh.org with a donation, please click here **.

thank you for your reply, i just read the dev-team blog. i think i understand what is required, but i want to make absolutely sure i follow the right steps here.

i have already jailbroken and unlocked my 3G OS 3.0 before, so ...

1. create the custom ISPW 3.1.2 using PwnageTool 3.1.4
2. from itunes, option+restore to select my customer ISPW in step 1
3. then run ultrasnow again??? (this is the step i am not sure. i must run ultrasnow to unlock again, right? because step 2 only jailbreak)

You got it! Good luck

__________________
** If you just want to support hackint0sh.org with a donation, please click here **.

Yes the steps you describe are correct you must install ultrasn0w again from cydia after you restore with custom 3.1.2 ipsw

__________________
Please read the stickies and search the forum before posting!
----------
iPhone 3GS 32GB factory unlocked (3.1; Pwnagetool, Cydia, OpenSSH)
iPhone 8BG (3.1.2; Pwnagetool, Cydia, OpenSSH)

THANK YOU everyone here for being so helpful!!