I'm sorry for the delay. Are you booting from SD port 3?
If so, the boot arguments on the documentation are set with the following commands:
U-Boot > setenv loadaddr 0x12000000
U-Boot > setenv fdt_addr 0x18000000
U-Boot > setenv fdt_high 0xffffffff
U-Boot > setenv bootargs_base 'setenv bootargs console=ttymxc0,115200'
U-Boot > setenv bootargs_mmc 'setenv bootargs ${bootargs} root=/dev/
mmcblk0p2 rootwait rw video=mxcfb1:dev=ldb,LDB-XGA,if=RGB666 video=mxcfb0:dev=hdmi,
1920x1080M@60,if=RGB24'
U-Boot > setenv bootcmd_mmc 'run bootargs_base bootargs_mmc;mmc dev 1;mmc read $
{loadaddr} 0x800 0x2000;mmc read ${fdt_addr} 0x5000 0x800;bootm ${loadaddr} - $
{fdt_addr}'
U-Boot > setenv bootcmd 'run bootcmd_mmc'
U-Boot > saveenv
U-Boot > run bootcmd
I would recommend trying them. It seems that the kernel is starting but it's not finding the rootfs for loading it. Please check in which partition is contained and change the root=/dev/ parameter if necessary. Please let us know if this helps!