Yesterday, I had also problem configuring the BT-338 external GPS.
But then it was working fine.
I use TomTom 6.010 btw, and I dont think TomTom use the external GPS setting.
At first, I fiddled around with the external GPS without success.
Then I realized that I must create an OUTPUT COMPORT in the BT settings!
So, I set that and voila, it works.
However, the comport that I set is different compared to the one that I set in the External GPS -> hardware ... But TomTom still works.
TomTom set to use Other BT GPS at com port 6 [ saved ]
- Software com port set to 9
- Hardware com port set to 5
- Output com port set to 5
Galaxy Nexus (Official yakju build)
: Android 4.1.2 "yakju" stock ROM, stock recovery, rooted ... fastboot unlocked