Hi Brad,
I can't say for sure what the issue would be. If you're transferring the image from one eMMC to a newer eMMC it's possible you'll need to update Linux before it will boot. There are also some hidden boot sectors that can cause issues between eMMC board revisions. Likely if you put this question to the Odroid forum, they would want to know the color of the eMMC to find the revision number and the version number / type of operating system installed.