All firmware updates are done over the standard Arduino software. This is available for Windows, Linux and iOS. But we recommend to perform the update with a Windows computer. You can download the Arduino IDE and the Teensy-addon (required for PureControl V3 and Teensy setups only) here: Download Teensyduino AddonDownload Arduino IDE
To connect the controller to the PC, you will need a micro-USB cable. This is the same cable as used for most Android phone.
A detailed step-by-step manual can be found above depending on the chosen controller.