Jetson TX1 will not boot, how do I completely reinstall Ubuntu on it?

I upgrade from 14.04 to 16.04, which I now regret. After I upgraded, Ubuntu would completely freeze while I was in the GUI. I could still access the terminal though. I tried installing JetPack on my TX1 by setting it into recovery mode, but now it will not even boot. I do see the solid two green lights, but I don’t get any HDMI output. I have nothing I need on the TX1, so I want to completely reinstall Ubuntu 14.04. If you need any other information, please ask.
I’ve already spent a few hour trying and I am new to Linux so if anyone could help, that would be amazing.

Most likely the install and running of 16.04 is working fine…but the monitor configuration is failing. This is common. Typically ssh login, or serial console would work (serial console is recommended to debug what is going on because it is nearly immune to most failures). If interested in serial console see this:

In terms of just installing or flashing Linux, this is done with the driver package plus sample rootfs. JetPack is just a front-end for this plus extra packages. So you can use command line and flash with driver package plus sample rootfs, or you can use JetPack of the proper version for GUI.

A listing of L4T versions is here:

Should you choose to flash via command line, be aware that you can still add packages later via JetPack. Or with JetPack, you can choose to just flash and not install packages until some later date.

If you choose to simplify and use driver package plus sample rootfs, then you only need the micro-B USB cable connected. Networking requirements are for install via JetPack…and even then ethernet will not be used during flash…this use is after flash completes and the system reboots.

Basic info for driver package plus sample rootfs, assuming L4T R24.1 as an example (I think this was Ubuntu 14.04):

# You might run "df -H -T ." from the unpack location to verify
# this is a Linux partition type, e.g., ext4, and that you have
# lots of disk space, e.g., 40GB.
# Unpack (no special permissions required):
tar xjfv Tegra210_Linux_R24.1.0_aarch64.tbz2
cd Linux_for_Tegra/rootfs
# Unpack sample rootfs (requires root permissions):
<b>sudo</b> tar xjfv ../wherever/file/is/at/Tegra_Linux_Sample-Root-Filesystem_R24.1.0_aarch64.tbz2
cd ..
<b>sudo</b> ./
# Place Jetson in recovery mode. Verify by getting output from:
lsusb -d 0955:7721
# Run flash...permissions matter:
<b>sudo</b> ./ -S 14580MiB jetson-tx1 mmcblk0p1
# When it's done it'll reboot and be ready. If host was already
# set up as router, or if the router responds to the DHCP, then
# wired networking will be up. Using WiFi probably requires
# more steps.