OS Release: Ubuntu 18.04 for ODROID-U2 / U3
(Note: This should also work with the ODROID-X, X2 and Q, although it hasn't been tested.)
An ODROID user recently published a new Ubuntu 18.04 image on a 4.16 kernel for several classic models of ODROID boards that can still hold their own in speed tests against much newer boards.
Visit the maintainer's GitHub repo for instructions and information about the build.
NOTE: The author created the image to fit on a 128GB microSD card, so this image needs to be written to a card of at least that size. If you wish to install it to a smaller card, follow the link below to build your own image.
To recreate the author's project from scratch, follow the author's tutorial guide.