How to fix a mono CS0589 Internal compiler error during parsingSystem.FormatException error on the RaspberryPi

When you want to compile some C# code using MONO on Linux on your RaspberryPi and you encounter this strange error message:

error CS0589: Internal compiler error during parsingSystem.FormatException

You need to do:

  1. Update your Debian by running:

    sudo apt-get upgrade
    sudo apt-get update

  2. Upgrade your RaspberryPi firmware:

    sudo rpi-update

  3. Reboot your RaspberryPi
  4. Retry compiling – should work now.

The reason for Mono to crap out like above: Previous Mono versions and RaspberryPi firmwares where not compatible due to one side using HardFP and the other not.