Looking for help....
I just updated my MD-BT01 to 1.05 and it no longer works. It was great under 1.04. In fact, it is now seen as a UD model, which is incorrect. Previously, it was listed as the correct MD.
I can’t find a way to get back to 1.04. Or to fix it so the device is correctly seen as the Midi port adapter.
Help 
Interesting Rich,
The latest firmware for the MD-BT01 is version 1.0.4 _Not sure where you are looking to see the version number... but maybe this will help:
Plug the MD-BT01 into your MIDI device. Make sure your Keyboard is set to Output MIDI via the 5-pin MIDI Port. Ensure that MIDI OUT of your keyboard causes the internal red light of the MD-BT01 to flash... ensuring this is indeed the correct connection for OUT, plug the other end to the MIDI IN.
Open the Utility App
“MDUD-BT01”
Give it a few moments to detect your MD-BT01
It should report the current version:
1.0.4;
If you touch the line item it will allow you to RENAME the device and to check for FIRMWARE Updates.
Select "Firmware" -- it should indicate the latest firmware available for download:
New Version V1.0.4
Even if you don’t understand this and you were to attempt to update anyway... the update will download and install
1.0.4 AGAIN!
When successfully completed it will again indicate that the current firmware is
1.0.4 and the latest download is
1.0.4
At the very bottom of the App it says that version of this App “MD-BT01/UD-BT01 Utility is "1.0.5" (please do not confuse this with the version of your Yamaha BlueTooth device) V1.0.5 that’s just the version of the Utility App itself.
Let us know.