Problem after upgraded iPad 2 to iOS 5 [fixed]

I have an iPad 2 with wifi only, and I always connect to my iPhone 3GS (iOS 4.3.5) through Bluetooth and then using the "personal hotspot" on iPhone, I can share the Internet connection and do lots of stuffs on the net with the much bigger screen.

However, after I upgraded my iPad 2 to iOS 5 yesterday, the Bluetooth connection still works, but it can't get any Internet connection any more!

This is really annoying. I guess can also upgrade my iPhone to iOS 5 to see if that would fix the problem, but there's first of all the risk that it still won't work, plus I will then loose a device for testing with iOS 4!!

What a pain, any one having similar issue?

[UPDATE] saw quite a few people experiencing similar issue with iPad after upgraded to iOS 5 - but mostly for connection through router, some of them got it fixed after router restarted. So I tried that too - I power off and then restart my iPhone. And guess what, it works! But why a restart is required is still a mystery to me...

Posted in: iOS 5