Hi,

after around 3 months when I was forced to do a restore of my iphone to 3.1.3 without SHSH blob saved I finally managed to jailbreak it. It is true that I had to spend some money.
To make things short I found on youtube a way to activate the iphone 3GS without the original simcard buy buying a dits Phonebook card.

After I've put this sim to my 3.1.3 Iphone I managed to activate it with iTunes then I just used Spirit to jalbreak the phone and installing the last version of ultrasn0w did the trick for me.

Unfortunatelly the phone is still on 3.1.3 and not on 4.0 or 4.0.1 as I would like but still at least I can use it.

If someone find a way to jailbreak 4.0 on 5.12.1 bootrom just post a replay please.

Ten thousand threads about it ^^

There is no untethered jailbreak for iOS 4.0.x on new bootrom 3GS

tethered jailbreak is possible in theory if you have your 3.1.2 SHSH but in reality this is only useful to those working on making new jailbreaks.

Wait. The new jailbreak from the guy behind spirit is coming any day now.

Backup your SHSH while you are waiting and take the time to read existing threads before posting the same question 10,000 others have posted already.