Hi,
Might not be related or then it might.
I am using the SolidRun debian image, and I was not either able to boot from eMMC, until I did update the SPL and u-boot.img from here https://github.com/SolidRun/u-boot-imx6.git.
Also the uEnv.txt needs to point to the eMMC device.
Since I had already fused the board, it wouldn't boot from SD anymore, so I did compile the SPL/U-Boot and placed them on a USB stick. Then I can choosed boot device from the u-boot (press key during boot) and could boot from SD, after that write the SPL/U-Boot from USB stick towards the eMMC.
I used this as reference, http://forum.solid-run.com/viewtopic.php?f=8&t=3259&p=21981&hilit=spl#p21981
I noted that you have fused board and have not set the MAC address, the ethernet interface will most likely not be up before it is set.
Regards,
Sebastian