I’ll admit this is a bit hackish, and not everyone’s cup of tea. But for those of you who might find it useful, Parallels actually works great to bridge the gap between Catalina and Elektron. At least when it comes to firmware updates.
So if you’re wanting 1.40a/1.50a for your A4/RYTM and are stuck on Catalina, you can grab a trial of Parallels here and it will automatically download/setup Windows 10 for you. After that, you can just install Overbridge/C6/Transfer/whatever and at the very least update your machines.
The process is pretty straight forward – You’ll want to have Parallels running and Windows 10 booted, and then when you plug in and power on the device, Parallels will ask you if you want Windows to take the usb connection from macOS. You’ll want to give the connection to Windows. At which point, Overbridge on Windows will recognize your device. You can then C6/Transfer/Overbridge as normal inside of Windows.
There may be a way to route the audio from an Ableton session in Parallels/Windows over to Ableton in macOS, making for an actual Overbridge “solution” but I haven’t explored that yet.
Anyway, hope it this helps someone. It helped me ¯_(ツ)_/¯