20 - 30 minuten
I hate telephones. Always have. But my wife and I were going to Great Britain, and we might be in separate places and might need to contact each other. Also, her iPhone5 was locked to AT&T, and we might need a cheaper way to make phone calls home. The solution was to revive her ancient iPhone 3gs, unlock it, and get a cheap UK sim to use in the UK.
The iFixit instructions were awesome, both the video and the web page, and I got through it, slowly and carefully, in something like two hours. I was very pleased with myself. I'm pretty technical, but at age 67, my eyes are not what they used to be and some of those connectors are REALLY tiny. Especially the little tab that flips up to hold connector 3. But I got it done.
One problem. The battery did not come 50% charged. It came pretty much dead. On turning the device on, I got a black screen. Plugging in the power, I still got a black screen. I thought I had bricked the thing, but I left it plugged in. About 30 minutes later, the screen came to life, but only with the dreaded "Red Battery". But I still left it plugged in. Another hour later, I got a green battery, with a 10% charge, and normal behavior; IT's ALIVE! After that, everything went as expected.
The old 3gs served admirably with a UK SIM and I was able to call locally and back to the US with and old phone and a cheap Lebara UK SIM. Clear as a bell. Who needed a new phone?
1) The iPhone 3gs replacement batteries are probably getting a little stale by this time. It might take a couple hours charging to wake one up.
2) Read the instructions very carefully about connector #3; it's a lever and tab connector, not a snap-on like the others.
3) At this point in history, unlocking an old AT&T iPhone was pretty easy; AT&T has a web page for the purpose; put in the right numbers and you're done. I attempted a similar maneuver with my daughter's old Sprint iPhone, and Sprint seems to be incredibly hostile and obstructionist about unlocking. If a phone has ever been a Sprint contract phone, just throw it away. It's not worth your time trying to convince them to unlock it.