Trying to get an example working with my device...

Thanks @Gordon -- I don't think the crash was the oxff issue, it seems to have been related to the 0x prefix on the UUID's. I've actually now had the code work -- once only. It must have been in some sort of state from my trying other things, but I haven't repeated it. I'll spend some more time early next week and try to track it down better, as well as try other methods to reliably connect. The device is a connectable beacon, transmitting every 1.35 seconds, so I imagine I'm just not synching up. I'm trying extending the scan time, but so far it isn't working reliably.