FiiO-BTR3 DAC

From ArchWiki

From the manufacturer's website:

The BTR3 is a Bluetooth amplifier which supports multiple wireless audio codecs (i.e. AAC, SBC, aptX, aptX Low Latency, aptX HD, LDAC, LHDC and HWA).

Installation

PulseAudio has issues with supported high sample rates - set them in the configuration as default: 

/etc/pulse/daemon.conf
default-sample-rate = 192000
alternate-sample-rate = 48000

If your device still is not working, try updating the firmware.

Firmware update

Install the dfu-util package, and download the firmware:

1. Power on the BTR3 2. Hold the unlabeled button for 5 sec 3. Hold the unlabeled button and vol + button for 5 sec 4. Check if the device is found: 

dfu-util -l
Found Runtime: [0a12:ffff] ver:2520, devnum:125, cfg:1, intf:2, path:"1-6", alt:0, name:"UNKNOWN", serial:"ABCDEF0123456789"

5. Optional: Backup your firmware: 

dfu-util -d 0a12:ffff -U backup_fiio_btr3.dfu

6. Flash your new firmware: 

dfu-util -d 0a12:ffff -D BTR3-1.2-0531.dfu

7. If dfu-util ends with an Error because the device was rebooted - you are finished