Talk about perfect timing. Just when I wanted to take my iPhone 3GS to Sri Lanka, they released the unlock for 3GS. I had iOS5 installed on the 3GS, and the new jailbreak and unlock works for 5.0.1.
So following the guide below, I managed to unlock my 3GS, which is on the new bootrom. BTW, I unlocked it on the MacBook Air, because the PC doesn't have internet yet. :D
Since I don't have a SIM card of another carrier, I thought maybe if it worked fine, it should also recognize the Softbank SIM card without a problem. Maybe it doesn't really mean it is carrier unlocked, but I wanted to check.
So I removed the MicroSIM card from my iPhone 4S, and inserted it to the 3GS using the MicroSIM card adapter I had bought from eBay a while back. When I booted iPhone 3GS, it worked fine. The service was recognized. I was happy. Maybe it didn't mean anything. Only way to find out if it really worked was by using my Mobitel SIM card back in Sri Lanka.
To the fun part...
When I tried to take out the MicroSIM card out of the iPhone 3GS, something bad happened. It got stuck. I couldn't get it out any way I tried. OK, time to panic!!
I googled for a solution and people were saying that they managed to take it out by disassembling the iPhone. Yikes! Well, what can I do, right? Luckily I had the tools to open up the 3GS. I had bought a Home Button repair kit from eBay a while back. Although it wasn't useful, because I didn't see anything wrong with the existing Home Button. But it is still pretty hard to press. That's another discussion.
Back to the problem at hand. I managed to take out the LCD screen, and then there were 3 cables, which I tried not to disconnect. But when I fiddled to take out the SIM card, I accidentally got them disconnected. Dammit! Anyways, with some pushing from inside, I managed to take out the MicroSIM card. Phew! One problem fixed.
Now to bring back the 3GS to life. There are three connectors. The connecting back the connector number 1 and 2 was straightforward. But I couldn't figure out how to connect connector number 3. I searched for YouTube for a video and finally found out something that really showed how to connect it back.
After some trying, I managed to slide it into the socket and lock it. Then I connected the other two connectors. Then I logged straight into Skype on the 3GS (n WIFI of course), and tested if the earphone and proximity sensors were working. The connector number 3 is responsible for that. It worked great.
Now, in 12 more days, I will be able to see if the 3GS really got unlocked. Either way, a morning with a lot of happenings.