The manual that 8bitdo offers is not complete so I decided to write down what I found out about the controller. For example, the manual does not tell you that you can indeed turn the vibration feature on or off. I thought that a firmware update might fix it but it actually didn’t.
Key Combinations (while plugged in)
L + R + Select: Toggles vibration
Star + Any key: Toggles turbo feature for that button.
Key Combinations (while plugging in)
L + R: Firmware update mode
This exposes a USB drive that a firmware file can be copied on. You can get them from https://support.8bitdo.com. It did not work on Linux in my case and the controller wouldn’t start up after copying the file on. It did work when I copied the .dat file with Windows XP, though.