NB: If you install the board image you are overwriting vendor u-boot with vanilla upstream u-boot; which a) has no "hold the power key to switch OS" mode, and b) there is now a single OS installed so nothing to switch between anyway. If you want that functionality you need to use the "box" image and configure it for the WP2 (or Hub, as appropriate) so that you retain vendor u-boot.
https://www.dropbox.com/s/tw6bg3kipc8t…wp2.img.gz?dl=0 <= dd backup of the WP2 factory image
You happen to have a dd backup of the Wetek Hub factory image?