I'm having the same exact issue with my Curve 8320.....Must be a know issue by now?

I have tried everything- Using the T-Mobile LinkSys router. Even got rid of all my 2.4GHz cordless phones in the house and switched to 5.8GHz

Stays on UMA for long periods and then kicks off back to EDGE.

When it kicks off to EDGE have difficult time getting system to find UMA signal again.

Support had known issue with people who had previous BB but this is a new Curve8320.

Tech support has had me do a complete wipe 3 different times….no help????

Anyone have a suggestion?

Upgraded OS to 4.2.2.175 yesterday afternoon. Stayed on UMA all day and that evening. Best results I have ever had with this 8320. When I woke up this morning, it was back to EDGE, but quickly found UMA on it's own. It never found UMA on it's own before. I see a problem still when 8320 goes into deep sleep mode. Overall big improvement with new OS.