Darkircop have released their tools for reverse engineering CSR Firmware. The tools include a disassembler dis.c for disassembling official firmware. An assembler as.cc for writing your own firmware is also included. With these tools you are now able to write your own firmware for your CSR based Bluetooth Dongle, which might even include raw access for Bluetooth sniffing. The source code for sniffing Bluetooth under Linux included, too.

It might even be possible to port the techniques for finding hidden Bluetooth devices described in this paper onto a CSR dongle. In the paper GNU Radio with USRP was used. The source code used for this attack can be downloaded, too.