8X SBC Pro "Unrecognized filesystem type" error at boot

I just acquired ConnectCore 8X SBC Pro and tried to program the yocto firmware. Followed the steps from the link : Step 3 - Program the Yocto firmware | ConnectCore 8X. SD Card and USB mass storage methods failed. Connect Core freezes right after the command “run install_linux_fw_sd” or “run install_linux_fw_usb”. After that i realized the error message at the boot up.

** Unrecognized filesystem type **

Any idea about the cause of this error? How to solve it?

Thanks in advance.

check the “bootcmd” with printenv bootcmd
likely you are trying to boot from a non-existing parition, or the flash was not partitioned correctly, or the boot partition was not formatted or not programmed with the correct Linux firmware.
Another option: your U-Boot version is too old. Update to a newer U-Boot.