How to use U-Boot on NXP i.MXRT1050 EVK
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- Build U-Boot for i.MXRT1050 EVK:

$ make mrproper
$ make imxrt1050-evk_defconfig
$ make

This will generate the SPL image called SPL and the u-boot.img.

- Flash the SPL image into the micro SD card:

sudo dd if=SPL of=/dev/mmcblk0 bs=1k seek=1; sync

- Flash the u-boot.img image into the micro SD card:

sudo dd if=u-boot.img of=/dev/sdb bs=1k seek=128; sync

- Jumper settings:

SW7: 1 0 1 0

where 0 means bottom position and 1 means top position (from the
switch label numbers reference).

- Connect the USB cable between the EVK and the PC for the console.
(The USB console connector is the one close the ethernet connector)

- Insert the micro SD card in the board, power it up and U-Boot messages should
come up.