For people wondering about install (tried with TWRP):
1. Nandroid backup
2. Factory Reset
3. Grab toro_ubuntu.zip and quantal-preinstalled-phablet-armhf.zip
4. Flash toro_ubuntu.zip
5. Flash quantal-preinstalled-phablet-armhf.zip (this one will take a while, grab some coffee )
6. Reboot (screen will go black but after a few seconds Ubuntu is up)
This install didn't wiped my sdcard. I just restored my TWRP backup after a short Ubuntu testdrive.
If you are paranoid, just copy your stuff from SDCARD to your PC before flashing.
EDIT: Exparimental (untested) build that may enable calls and data. Same process as converting android from GSM to LTE, so I don't see why it wouldn't work. Any takers? (replaces the toro zip above)
EDIT: Data isn't even supported on the GSM, so unlikely to have any data, but calls should work.
EDIT2: Test appears broken, but I'll leave it here for others to look into on why it doesn't work. It should have been merged in correctly, not sure why it's not working.
The only thing I did was modify the line so that the zip would be willing to flash to the toro. It does not have CMDA/LTE connection, but it does flash and work on WIFI just fine. With it's limited uses ATM, I believe that getting working radios would be useless. Try it and see what I mean. Do not wipe system, or it will not boot.
Sprint thread is here