#turn bluetooth on:
sudo /etc/init.d/bluetooth restart
# make it automatic on boot
sudo systemctl enable bluetooth
# reinstall bluetooth
sudo apt --purge --reinstall install bluetooth bluez blueman pulseaudio pulseaudio-module-bluetooth
# at
sudo nano /etc/pulse/default.pa
# add load-module module-bluez5-discover
# then
sudo killall pulseaudio
pulseaudio --start
sudo systemctl restart bluetooth.service
cd /lib/firmware/rtl_bt
sudo ln -s rtl8761b_config.bin rtl8761bu_config.bin
sudo ln -s rtl8761b_fw.bin rtl8761bu_fw.bin