Troubleshooting controllers can be aided by observing the CPU light
- Continuum controllers
A video created to show the differences between Normal, Error and Bootloader modes
This will not tell you specifically what mode the controller is in, but it can offered to try to help to determine the mode.
The speed of the CPU light on some of the controllers may vary, but this gives a general idea.
Normal Mode is on the left, Error Mode is in the middle and Bootloader Mode is on the right.