$ sudo dmesg | grep 'firmware load for' | grep 'failed with error' $ sudo dmesg | grep 'firmware: failed to load'
This will search your diagnostic kernel logs for failed firmware loads and will produce lines that look similar to the following
[ 53.168802] bluetooth hci0: Direct firmware load for qca/rampatch_usb_00000200.bin failed with error -2
Take that file name and pass it to
$ sudo apt-file search qca/rampatch_usb_00000200.bin
Which in this case will yield
$ sudo apt install firmware-atheros