Wiki Odroid plus USB troubleshooting and GPIO upgrade notes
User:Definitionofis confirms success running Ubuntu Linux with download links at that website link (above).
USB troubleshooting note: Some report USB issues, which might have been a dirty connector problems cleaned with alcohol. I am not sure. I can say with certainty the August 2018 version has no issue with recognizing all the USB devices. I read others commenting on USB problems with the spring of 2019 versions, but maybe it was their connector. I downgraded to August 2018 and now my USB works for all devices.
HOW TO ACCESS pin 5 of CONNECTOR 11 GPIO of Odroid XU4 by modifying the excellent wiringPi library, which works with XU4 but was originally designed for XU3.