Step 1- Unplug the USB cable.
Step 2- Open the QMK Toolbox.
Step 3- Press ESC key and plug USB cable (do not release ESC key). Luminkey80 will be in DFU mode, and QMK Toolbox will show words in yellow ‘DFU device connected’
Step 4- Click ‘Open’ and choose the Bin file for Luminkey80. Then click 'Flash’. QMK Toolbox will show the update program. (do not unplug the USB cable while updating).
Step 5- Wait seconds, The firmware flash is complete when you see the content below.