I have a few suggestions for developers using bleeding edge systems on iPhone.

1. The OS will expire. Be sure you update to the latest available system before you, say, go out of town to Railsconf. We’ve been warned you don’t use OS3 on a production phone, but that’s easy advice to ignore when things seem to be going swimingly.

2. Download every beta OS for your device even if you don’t expect to use it. I found OS3 beta5 won’t install on this iPhone. I don’t think I’m alone here, but it might only affect the original iPhone. I had to go to a beta4 to get running again.

3. If you do find you can’t run the latest beta, mangle the Apple URL to download an older image. Since I didn’t have beta4 downloaded, what I did was copy Apple’s URL for the beta5 image, change the fives to fours, and amend the build number. I was already logged in so when I told firefox to follow that URL, it just worked. whew.

4. Be aware of iTunes tricks. I’ve been using Xcode’s organizer to install the OS, but it’s also worth trying iTunes, especially if you’re having issues. It didn’t help me install beta5, but a colleague was able to do it this way on a 3g iPhone. You have to option-click “Restore” in the iTunes device management screen. Also, be sure you have the latest iTunes. The 8.2 prerelease is required for beta5.

OS3 is great fun and if you have a developer account and device you can spare, I recommend spending time on it. We have some great features coming and I predict we’ll see an avalanche of new apps using push notification in particular.