Bought a new router, a T-Mobile Personal CellSpot Router.
It's basically an Asus RT-AC68U with T-Mobile branding and firmware, a 1900AC router which I caught on sale for $59. Replacing the T-Mobile stock firmware was a bear, and took me all evening.
1. I had to boot into recovery mode to downgrade to a firmware that supports telnet, then reset the nvram.
2. I then had to downgrade the bootloader using a USB key and some fancy telnet commands to a version more tolerant of 3rd party firmwares. This required saving the existing bootloader, hacking my router's MAC addresses and WPS secret into the replacement, then committing. And reset the nvram again.
3. Then I had to reboot back into recovery mode, but the web server never would fully serve the recovery page. I had to tftp my chosen firmware with no GUI and no feedback indicating pass or fail, just a prayer that it wouldn't brick. It didn't.
One more nvram reset, and now I'm running AdvancedTomato. Whew.
Anyway, Amazon currently sells the non-T-Mobile version, the Asus RT-AC68U, for $156. This T-Mobile stamped dealio was a steal.
By the way,
the sale is still on for anyone else who's interested. It's $99, then promo code WIFI40 knocks $40 off.