MICROMIDITRS-USB 1.5 for Adafruit QTPy
Firmware is available as a pre-compiled UF2 file.
To load the firmware, connect the QTPy to your computer and then double click the reset button on the QTPy to drop it into bootloader mode. This should now show you a QTPY_BOOT drive on your computer desktop. Drag the UF2 file to QTPY_BOOT and it should dismount/reboot and come back as the MMTRS-USB.