A few months ago I did an interesting discovery about using my cellphone to go on the internet via bluetooth. I had this strange situation before where it just stopped working, and after revisiting all configs it worked again.

What really happens is that my cellphone somehow crashes, after which I power cycle it by removing the batteries. The phone then boots again, but here is the twist: the service channels in the phone are re-allocated and apparently in a random order!

This implies that the RFCOMM channel configured in the /etc/bluetooth/rfcomm.conf file is possible wrong now!

Solution: just browse the services again with sdptool browse, adapt the file and it should work again!