Ok,
Lets see if a software refresh helps.
Either order a new micro SD card from Brennan, or get if you have an SD card reader on your PC, get one from a shop ( anything over 8 Gb will do but no need to go over 16), then using the instructions on the Brennan web site, flash the software on to it.
You will need to take the back off the B2 to get to the SD Card (unless your B2 is old with a card sticking out of the side in which case you need an SD card not a micro SD Card). To get into the back you just undo the top 2 screws and just pull the back out about 4 cm to see the sd card slot.
Once you have the new SD Card in - from Brennan or your own, the first thing to do is a web upgrade to make sure that you are using the very latest version, as the Brennan card or the downloaded version will be slightly out of date.
Try this for a bit and see if it cures the problem.
Fred