Download .zip with firmware and bash script:
Disconnect DC power, connect Quadruple to your MAC using micro-USB data cable
Find port of your quadruple in terminal:
ls -l /dev/cu.*
Unzip downloaded file, edit .sh file and modify line 16 with
Change XXXXXXXXXX to the port found in previous step and save script file
Run script in terminal:
Perform “factory reset” after flashing (A+D hold on boot). Check manual.