I can report an identical problem on my Orange branded Bold 9700. Very intermittent UMA connection via BT Home hub (older white one). When connected works well - but this is rare. I live in poor GSM/3G coastal region and am able to register with French and Belgium networks if allowed to roam. I therefore have the mobile network set to 'Manual' on Orange UK and have the 'Connection Preference' set to 'Wi-Fi preferred'. I also read elsewhere that having Bluetooth switched-off fixes the problem. This is not the case for me - makes no difference on or off. Also tried a battery-pull - no change. Reset BT Home Hub (held back button >20secs) and updated the firmware - again no change.
Eventually I contacted Orange CS (customer support) on 14th June 2010. Was eventually put through to 2nd level support to a very competent guy (Gareth) who provided me with his number, took a detailed description of my symptoms and gave a promise to call me back. He did so and explained the following:
Orange CS have three layers of technical support:
Level #1 These are the people who fend off the most basic of questions - "how do I switch on my phone, if I have orange hair do I get a discount...."
Level #2 These people are able to talk a good degree of tech, but are more interested in gathering detail to pass onto Level 3.
Level #3 These people apparently rarely 'speak' with Jo Public. They take feeds from Level 2 and work internally and directly with RIM (where appropriate) to solve deeply technical problems which one assumes means software bugs which RIM add to their 'fielded QA' list.
In any case, Gareth from Orange said that Orange were aware of this exact UMA problem and that we 9700 users should either expect a phone OS update or see the problem disappear. He confirmed that the BT Home Hub was not to blame. He said that any ISP's connection should enable UMA if working correctly and there are no specific issues requiring you to have Orange broadband. He led me here:
On your BB, if you simultaneously hit Alt and Left-Shift keys, then hit 'H' this will bring up a 'Help Me!' screen.
I am apparently running the latest version on my Bold 9700:
Vendor ID: 142
App Version: 126.96.36.1996 (994)
I called Orange support again today. Gareth is off but his colleague read through internal notes on this subject. Many, many Orange customers are reporting this problem. The notes before her revealed that the issue is perhaps not RIM (i.e. device dependant) but is looking more likely to be Orange's UMA networking failing. Gareth was given an action to call me back towards the end of this week with a status update as she is not in Level 2.
So I guess its now time to wait or return the product. Hope this helps.
P.S. Just a quick note that UMA has been running perfectly all day today - odd?!
P.P.S. Orange support can be contacted on 07973 100 150