Flashforge Creator Quick Start Manual page 22

The reset switch is on the back of your Creator, just to the right of the USB port. You'll
probably also need something to press the button with -- most fingers won't fit.
Hit the upload button, press the reset button, and wait
Hit upload, wait a fraction of a second, and then press the reset button.
It will take a little while, but soon you should see a message telling you that your
firmware has been updated successfully.
Once you see the "Firmware update succeeded!" message, you're set! Go back to
printing with your exciting new firmware.