I guess because I'm a glutton for punishment, I tried using my new Stowaway Sierra BT folding Keyboard (STBT01) driven solely by the WM6 built-in keyboard driver. All works well...for awhile. Eventually, usually after turning the radio off and then back on, on a subsequent attempt to turn on the radio (to connect to the keyboard), I get an error indicating that the BT radio failed to initialize due to insufficient driver memory, and prompting me to do a soft reset to restore the radio.

Clearly, with 128MB of RAM, there's plenty of RAM available (and just to be sure I checked and there was 60MB free).
However, after 2 consecutive days of using the Sierra BT Keyboard driver, I have not seen this error recur. Could it be that the BT Keyboard driver that comes with WM6/iPAQ211 is the problem? Has anyone else seen this?