Или обновлять Boot или лить прошивку в режиме Boot
https://www.analysisman.com/2018/01/extreme-switch-reset-to-factory-default.html
Additional Notes:
In Boot Rom v2.0.2.1, the config none command has been removed for security reasons. It was added back into Boot Rom v2.0.2.3.
If the config none command is not present, the only way to default the switch from boot rom is by loading a rescue image (see How to use the Boot Rom menu to tftp download a new image to the switch).