You will only need a computer and a USB cable to update firmware contained in Matrix Ctrlr MCU board based on arduino.
Update from raw .hex file :
You have to select the Matrix_Ctrlr_vXXX.ino.with_bootloader_mega.hex in your Loader or HexUpLoader software and set the rate to 115200 and the appropriate COM port (check the number inside your Windows/Mac hardware configuration).
App for Windows :
alternative to using xLoader with Windows 8.1 (french)
App for Mac :
Hint : upload the version with boot loader if you want to make future updates using arduino IDE. Set baud rate to 115200.
Update from Sources :
You will notice a lot of option in the sources and the possibility to extend the features of the Matrix Ctrlr. Experiment, test, do what you like, all is free and open source 🙂