Thank you for your feedback.
This error code means “USB device is already opened”
Please make sure the LP-16 not selected as default interface in your Audio Midi settings panel.
Also make sure there’s no other audio related application running on your MAC during the firmware update.
Please try the following thing:
1.Connect the LP-16 to your computer.
2.Turn it off then reboot your computer, but leave the LP-16 connected (turned off)
3.After the reboot process, start the firmware updater, when the application running please turn on the LP-16.
If still not success, remove the LP-16 but leave turned on, exit from the firmware updater then start it again and connect the LP-16 in turned on state.
I looking forward for your feedback