EDIT (2018): Mediatek mt7610u was supported in-kernel starting with Linux kernel 4.19, so upgrade your kernel if you are running into issues! Getting this to work in 4.15 has been basically impossible.

Wifi on Linux is still puzzlingly terrible. I bought a new card (TP-Link AC600 Dual Band USB Adapter w/ External Antenna) because it was supposed to have Linux support, but the manufacturer-provided drivers were only for Linux Kernels up to ~3.1 and I’m on 4.4.

> cat /proc/version

Linux version 4.4.0-38-generic (buildd@lgw01-58) (gcc version 5.4.0 20160609
(Ubuntu 5.4.0-6ubuntu1~16.04.2) ) #57-Ubuntu SMP Tue Sep 6 15:42:33 UTC 2016

OK, time to google. I found many references to this advice circa September 2015, which advocates use of a modified driver from github. After reboot I got a kernel panic, so I looked through the pull requests and found one critical fix that hadn’t been accepted upstream yet. Installed this driver instead, then did the following:

# Got the USB card recognized by loading the driver module.
sudo modprobe mt7610u_sta

# Bring up the interface.
sudo ifconfig ra0 up

# Modify the network manager config to set managed=true, forcing network manager
# to manage my silly network card.
sudo vim /etc/NetworkManager/NetworkManager.conf

# Reload the network manager.
sudo service network-manager restart

Card works now.

Since I didn’t use DKMS, if the kernel gets upgraded I’ll have to reinstall this driver.

Looks like the most active version of this driver is not the one I used, but this one: https://github.com/chenhaiq/mt7610u_wifi_sta_v3002_dpo_20130916. If I had to start over I guess I might use that branch instead, seems like a bunch of fixes are applied on it.