What iPhone 2.2 software have some bugs on it ? palmaddict reported some of them that you might want to look at.
Third-party Applications broken. Some third-party applications will no longer function properly under iPhone OS 2.2 due to API changes and other modifications.
"Could not Connect to Internet". Some users are encountering an inability to connect to the Internet over cellular networks after the iPhone OS 2.2 update. In some cases, this issue can be resolved by switching from 3G to EDGE (or, for carriers other than AT&T, the appropriate GPRS network).
“SIM card not inserted”. Or PIN lock Some users are receiving an error message indicating that the SIM card is not inserted, or that a PIN lock is in place when none should exist. If you get the PIN lock message, try the suggestions in this tech note.
Kilometers instead of miles in Google Maps. It appears that Google Maps for the iPhone now displays kilometers instead of miles for various countries.
Problems deleting email. Some users are unable to delete emails from certain accounts, especially AOL accounts after the 2.2 update.
App Store extremely slow. The App Store is extremely slow after the iPhone OS 2.2 update for some users. This may be a server-side problem that Apple will resolved shortly.
