dv505, as I can see from next post from DarkAllMan file imx6q-cubox-i-som-v15.dtb is correctly loaded. But not sure what is wrong after that.
DarkAllMan: did you enabled serial console in uEnv.txt file? It should look as
# make boot more quiet
#console_arg=quiet morequiet
# or having quiet and serial console
#console_arg=console=ttymxc0,115200 quiet morequiet
# show messages in serial console
console_arg=console=ttymxc0,115200 no_console_suspend=1
Then you should see some boot messages from kernel.
Anyway, in mine image with 3.14 kernel there is little newer u-boot used. I will investigate this but I don't have any device with SOM v1.5 (only CuBox i4Pro).
pssturges, thanks for reporting back.