Hey guys,

I've trawled through the internet and looked at pretty much all the articles I could find but can't seem to find an article which answers my exact question. I'm not intending to spam - I promise!

I own an iPhone 3GS version 3.1.2, model MC131X, Modem Firmware 05.11.07 and a serial number which begins in 86945...

I bought it a while ago and it was jailbroken with Blackra1n but I'm going travelling soon and cannot afford to have a tethered jailbreak as I won't have access to computers to turn my phone on again after I turn it off / it runs out of battery.

So I'm hoping to restore my iPhone to it's original state and then do an untethered jailbreak. Losing apps doesn't matter to me and I've already backed up photos and contacts. Could anyone point me in the right direction? I've read articles that 3.1.2 has been stopped but how we can't jailbreak 3.1.3...and then Spirit got released, etc. Super confused at the moment.

In short, I just want to restore my iPhone and conduct an untethered jailbreak. Any help/advice welcome!

- J