The file openwrt-mt1300-3.211-1112.bin caused significant issues. My first attempt was using the “Save Settings” option during the upgrade. After the update, the router IP defaulted to 192.168.1.1. I was able to log on but none of the menu items worked and it would not connect to the saved wireless access point as a repeater. Hard wiring it to my router did allow me to access the internet.
The same issue was seen after a flash through uboot and clean install.
The file openwrt-mt1300-newdriver-3.211-1112.bin does seem to work. I have it installed now and I’m testing it today (before my next trip in about a week…). No issues so far on either 2.4G or 5G.