I purchased my iPhone 4 around July of 2010, so it’s almost 2 years old. It’s been rock-solid until about a month ago when the “Home” button was working intermittently (i.e. pressing it didn’t activate the phone); tried hard-resetting many times, doing restores, etc., without success.
What fixed it was merely:
1. Get a dust blower or use your and lung power
2. Blow into the power slot (in the bottom) and into the “Home” button. (Note: Press the “Home” button and blow into it from different angles.)
3. Repeat #2 a number of times.
4. Voila! That’s it!
If it worked, the button should have that “clicking” feel once again (I didn’t notice/realize this until after I started having the problem).
Bottom line: Dust in your phone (or everywhere else), especially, in the controls is not your friend.
UPDATE (3/21/12): It started acting up again, despite the fix mentioned above. This is what I found this time, so keeping my fingers crossed (it’ll cost around $150 to get the button replaced at the Apple Store):
Worked for me….
1. Open any application, e.g. Messages.
2. Press and hold the power button until the slide to shutdown bar appears.
3. Release power button.
4. Press and hold Home button with normal pressure and wait until screen returns to icon screen.
5. Enjoy your functioning Home button!
From what I’ve read, this procedure recalibrates the Home button after normal wear or heavy use.