I had this issue even before upgrading to iOS4 (Even after upgrading I'm still having the same issue) so I don't think it is related to iOS4. Sometimes I'll see my full bar dropped to NOTHING then suddenly my 3g icon decided to appear again and this happens almost every 30 minutes to 1 hour. Sometimes I have to do like what you did (Go into flight mode n out) Few of my friends using other phones are having the same issue as well so I think you should log a complain to Maxis about this and see what they can do about it. (I doubt they can do anything ) I guess more people complaining might have "Some" impact (even though they usually don't care) but give it a try anyway.

This post has been edited by derlin: Jun 28 2010, 02:54 PM

Yes I get that a lot. Especially when I'm playing games (Trying to get UltraCore in SpaceMiner! ) and suddenly SMS pops in and it hangs or when I try to launch another apps (Feeds, Safari, iPod, etc). To date, I've resetted about 7 times since upgrading to iOS4..

This post has been edited by derlin: Jul 1 2010, 08:59 AM

Please read the first page and you can find your answers easily there. It's not rocket science.

Multitasking - It's finally here! Double-tapping the home button will show all the apps you are currently running. This multitasking system is designed for minimum impact on battery life.

This post has been edited by derlin: Jul 1 2010, 02:44 PM