Ubuntu 18.04 hangs on boot with Nvidia driver 390 or 396 installed

I'm trying to get a second display to work via the HDMI port on a GeForce 1030. It works if I boot into Windows, but not in Ubuntu.

ubuntu-drivers devices returns:

== /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 ==
modalias : pci:v000010DEd00001D01sv00001028sd000011C7bc03sc00i00
vendor : NVIDIA Corporation
model : GP108 [GeForce GT 1030]
driver : nvidia-driver-390 - third-party free
driver : nvidia-driver-396 - third-party free recommended
driver : xserver-xorg-video-nouveau - distro free builtin

So I ran sudo apt get nvidia-driver-396 which succeeded. I setup the MOK password when prompted. I rebooted, then went through the "enroll MOK" flow. Ubuntu then shows the boot log for a time then hangs, the last command being "Started Network Manager Script Dispatcher Service" which I assume is irrelevant. I'm able to start a session with CTRL + ALT + F2 and uninstall the drivers with sudo apt purge nvidia*, then successfully sudo reboot.

I am also unable to boot with the nvidia-driver-390 version.

I checked out the systemctl log while it's hanging and it's full of repeated log items (could be suggesting infinite loop) from "nvidia-persistenced" that look like:

Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: Verbose syslog connection opened
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: Now running with user ID 123 and group ID 129
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: Started (1399)
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: device 0000:01:00.0 - registered
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: Local RPC service initialized
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: Received signal 15
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: Socket closed.
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: PID file unlocked.
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: PID file closed.
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: The daemon no longer has permission to remove its runtime data directory /var/run/nvidia-persistenced
Aug 23 17:23:48 brianubuntu nvidia-persistenced[1399]: Shutdown (1399)