The newest firmware of all devices is always included in the newest version of the PC software GHL Control Center (GCC).

The update is done through GCC, during the update process GCC finds the newest firmware for your device automatically.

In case you need direct access to the firmware files (e.g. for an emergency update) the firmware files are located in a directory similar to this:

C:\Program Files (x86)\GHLControlCenter_V1121\Firmware

(beginning of the path depends on the GCC version and the install location)