I have a fader not calibrating properly. I notice my software version is v2.1.0. So I downloaded the v2.1.2 software to update it. However I don't seem to be able to enter Boot Loader Mode.
The instructions say hold down Rec/Ready buttons on Channels 1 and 2 with the SELECT button on Channel 1 when powering up. This should enter Boot Loader Mode. It doesn't. It just boots up normally. This is the same for both the MCU and the Extender. I'm following the instructions completely and it just doesn't work. Any ideas?

Do this a couple of times and it will eventually work.   Mine failed the first two times I tried also.
 
You can also load the midi update file in Media player and upload it to the MCU that way.

I have tried dozens and dozens of times. Neither MCU nor Extender will enter Boot Loader Mode.