when I Download the images(IMX6Q) into the MMC on Ubuntu12.04，
I used cmd ：$ sudo dd if=u-boot.imx of= /dev/sdx bs=1K seek=1; sync
but I can not find /dev/sdx.
I have found mmc\SD card can not be loaded under Ubuntu12.04 system，
But I can use the MFGTOOS in Windows to download the firmware to the board
May I ask what is the reason？How can i solve it?