The undocumented settings will reset when you turn the G27 off, so that's not the problem. The G27 has no other option than 900 degrees so unless you're getting confused because the in-game cockpit wheel doesn't match your real life wheel rotation, you've got a hardware problem. But I seriously doubt it's that if the wheel calibrates.
Try this:
- Pick any open wheel car like the LCC Rocket, Caterham Seven, KTM XBow, a kart etc.
- Choose the chase camera (external, 3rd person, outside; the view where you can see the outside of the car)
- Hold the 'look back' button so you can see the front of the car
- Turn your G27 through 900 degrees and see if the wheels move. I'm sure that if the G27 is working, which it most likely is if it's calibrating (when it spins the wheel by itself when you turn it on) correctly, you'll see that the front wheels will steer. If they don't steer, test your G27 on a different game (if you have a PC but no racing sims you could try the rFactor or Race 07 demo). If it still doesn't work, it needs to be replaced.
