Also, it may be helpful to know how to restart your phone if it truely gets “stuck”/”frozen” for more than say 10 minutes, and pressing the “home” button on the iPhone doesn’t do anything, and pressing the “sleep/wake” button on the iPhone doesn’t do anything. First, try powering down the phone by holding down the “sleep/wake” button (the button on the top-right of your phone) for about 5-10 seconds. A red slider should show up on the screen and you slide this slider to the right to force the phone to power down. You can then turn the phone back on.

If that doesn’t work, you can try “force restarting” the phone, by holding down both the top-right “sleep/wake” button, and the bottom-middle “home” button at the same time for about 10 seconds. The phone should eventually just “flash” off, then turn back on and the Apple logo will show as it starts back up.

If all is lost and neither of these seems to work, or your phone is stuck in a sort of loop and just goes to the same thing even after a “force restart”, then you’ll want to do some googling on how to “recover” / restore your iPhone. Part of this process involves putting your iPhone into recovery mode:

To put your phone into recovery mode.. you can google for how to do this. Briefly, (assuming your iPhone is already on) while your iPhone is plugged into your computer and iTunes is running, you hold down both the top-right button of the iPhone (the sleep button), and the bottom-middle button of the iPhone (the home button) until the phone turns off. HOWEVER, unlike a “force restart”, you stop holding down the “sleep/wake” button right when the phone turns/flashes off, but you KEEP holding down the HOME button for about 10 seconds, typically until the screen shows a logo where it looks like an iPhone USB cord plugging into the iTunes logo or something. iTunes should recognize the iPhone is in the “recovery mode” and say say by prompting you with a message/alert about this. It may require you to allow it to “check” the iPhone version first, and then it may prompt you that the iPhone is in “recovery mode”.

Hopefully you don’t/won’t need these last few steps/tricks, but these are things that I’ve run into / learned in my history of working with iPhones.

1) Start with 2g iPhone. I’m assuming that you already have firmware version 3.1.2 installed (maybe because you put the iPhone in recovery mode and iTunes restored it to that version, or maybe you “accidently” updated).

2) Jailbreak the 2g iPhone using blackra1n RC3 from blackra1n.com (RC3 was released Nov 3, 2009).

There should be several tutorials out there for this step. Note that “jailbreaking” is not the same as “unlocking”. Jailbreaking lets you install custom applications on the iPhone, and unlocking allows you to “unlock” your iPhone to use different SIM cards, like TMobile instead of AT&T in the USA. However, you need to “jailbreak” your phone to “unlock” your phone (You use a custom application to do the “unlock” step on 2g’s. On 3g and 3gs phones, the “unlock” step is available directly from the blackra1n app that is installed on your iPhone after you jailbreak it).

3) Your phone has to be connected to a wifi network to do the unlocking step, at least the way I figured out how to do it. Make sure you can successfully complete a google search on your iPhone’s web browser, to verify wifi is working correctly. If wifi isn’t working, go to Settings > Wifi to check your wifi settings or find a local wifi network to join. Some people have trouble after the blackra1n jailbreak with wifi connections. You may have to Google about how to get wifi working again after blackra1n, there are several posts on it — i think you just have to do a “Network Reset” or “Network Settings Reset” which is located in the “Settings” application of the iPhone somewhere. I DID NOT HAVE TO DO THIS. I JUST HAD TO SELECT MY HOME’S WIFI NETWORK.)

4) After jailbreaking and making sure your wifi connection is working, go to the blackra1n application on your iPhone, and install “Cydia”.

4) Once Cydia is installed, you will need to use a tool called BootNeuter which you can install through Cydia (which was originally designed for iPhone firmware version 1.1.4, but still works even on iPhone firmware version 3.1.2).

To do this, find a tutorial online about how to use BootNeuter / what settings to use.

I used the tutorial here:
http://www.redmondpie.com/jailbreak-unlock-iphone-2g-3.1.2-firmware-with-blackra1n-rc3-9140086/

That redmond site also has some tutorials for the jailbreaking step that may be useful if you’re not familiar with the “jailbreaking” process, which is required at step 2 above.

I am successfully using a 2g iPhone version 3.1.2 firmware on TMobile in the US.

What can i do?