Just some of my personal experiences with the Gevey:
I bought mine here in Beijing, the guy told me of a complicated process which I tried for 6 hours to no effect. The launch screen is in Chinese so that didn't help.
What I do:
I shove the sim in, I never reboot, sometimes this takes 10 minutes or 10 tries to get the Gevey screen. Half the time I get invalid sim/ect messages.
Once the Gevey screen pops up:
I hit accept, then the phone is searching for signal.
The second that it finds one bar, I click on the phone and dial 112.
The call screen pops up (black) then loads my background image, once I see my picture, I generally take my time and push the home button.
Then I wander over to settings, and click on airplane mode.
Typically I have to wait 10-20 seconds, then it will say No Sim Card, then I take my time and flip it off. It takes another 30 seconds usually to get a signal and start up.
However, I live in a building with poor signal, 3 bars tops, two when I hold it. I think outside it will 'lock on' faster. Sometimes it doesn't want to do it, I will shove the sim in and out for 20 minutes straight. Sometimes I get a 'fake Gevey screen', this is when you get a bar of signal, then the Gevey screen pops up, and when you hit accept, it flips off.
When you get the Gevey screen you have one chance at getting a signal to '112' with.
Waiting 15 seconds IMO is stupid, because most of the time, this one bar will only stay 'alive' for 8-12 seconds. For me it does take many tries, but as long as I get a good Gevey screen and a bar 5 seconds or so after hitting accept, then it will work. If you have or get a bar immediately after hitting accept, IME it will not work, it is a 'fake Gevey screen'.
This phone pisses me off so much but I can't justify spending another $400 on an HK phone, the merchants here don't even want to buy my American phone, its radioactive.