If you can’t assign a MIDI keyboard to get it working in LPX 10.2.1 and if you see the notification like this“Please select MIDI Channel 1 on your _______________ Keyboard” you will need to:
1. Find Logic Pro X app in the Applications folder
2. Control-click the Logic app and choose “Show Package Contents”
3. Follow this path: Logic Pro X.app/Contents/Frameworks/MACore.framework/Versions/A/Resources/MIDI Device Scripts/
4. Here you will need to find the manufacturer and the model of your MIDI keyboard.
5. Then simply ZIP the .device file that corresponds to your MIDI controller/keyboard.
6. Delete the original .device file.
7. Reopen Logic Pro X