Captive Portal - how do I type in a manual MAC address in new update

At hotels I always just logged in on my phone, then typed my phone's mac address (which is different per wireless network) into the gl.inet slate ax and it would work. Now I can't enter manual mac addresses anymore. The new login screen thing never works. It is always a blank page. I want to be able to use a manual mac address like before. The new way sucks.

The last two Hotels I went to I ended up tethering my phone because the capitve portal feature on the Slate AX doesn't work anymore.

Please disable the VPN/ADG features, and login the GL admin panel.

May I know can the router Admin Panel page access/open well?