[U-Boot] i.mx6 board booting

I followed the following commands to achieve a successful booting of i.mx6 board using SD card dd if=u-boot.imx of=/dev/sdb bs=1k seek=1 The above command burnt the u-boot.imx image on the SD card though nothing was seen on SD card. Next the gtkterm configurations were set and after the board was started serial console output was interrupted(by pressing a key). U-Boot>> sf probe (to probe the flash memory) U-Boot>> sf erase 0 0x80000 (to erase the flash) U-Boot>>fatload mmc 1 12000000 u-boot.imx The above command throws an error -"Unable to read file u-boot.imx"

SO what can be the problem behind it and how can we overcome it?