When updating the firmware on the SPARK MAX, it is possible for the process to be interrupted or for the firmware to be corrupted by a bad download. In this state, the Status LED will be dark and the SPARK MAX will fail to operate. SPARK MAX has a built-in recovery mode that can force it to accept new firmware even if the controller seems to be bricked. The following procedure requires a small tool, like a straightened paper clip, to press the Mode Button, a USB C cable, and a computer with the REV Hardware Client installed:
With the SPARK MAX powered off completely, press and hold the Mode Button.
While still holding the Mode Button, connect the SPARK MAX to the computer using the USB cable. The Status LED will not illuminate, this is expected.
Wait a few seconds for the computer to recognize the connected device, then release the Mode Button.
Open the REV Hardware Client. The SPARK MAX will remain dark and it will not connect to the Client, this is expected.
Select the SPARK MAX in Recovery Mode from the REV Hardware Client
Press the Update Button
Wait for the Firmware Update to complete
Once completed the SPARK MAX will disconnect then reconnect to the REV Hardware Client. Select the SPARK MAX to start the configuration process