Yocto - u-boot for iMX6UL EVK

[nickbedbury]

I'm getting started with the NXP Yocto stuff.  I've followed the tutorials and built "core-image-base" and other recipes.

In the tmp/deploy/images/imx6ulevk/ directory of my Yocto repo, there are u-boot files/links like so:

I'm not exactly sure which recipe these files came from, but I assume the .img is a bootable binary.  This is the output for "file" info:

$ file u-boot-sd-v2017.11+gitAUTOINC+ca0c3f3fac-r0.img
u-boot-sd-v2017.11+gitAUTOINC+ca0c3f3fac-r0.img: u-boot legacy uImage, U-Boot 2017.11+fslc+gca0c3f3 for\270, Firmware/ARM, Firmware Image (Not compressed), 344176 bytes, Tue Mar 13 14:19:51 2018, Load Address: 0x87800000, Entry Point: 0x00000000, Header CRC: 0x0F9794F0, Data CRC: 0x01F24B80

Therefore I tried this command to write u-boot to an SD:

sudo dd if=u-boot-sd-v2017.11+gitAUTOINC+ca0c3f3fac-r0.img of=/dev/mmcblk0 seek=2 bs=512

But after powering up the EVK with the SD, I see nothing happening on the serial terminal...as if it's never running u-boot.

Can I use the .img file to boot my EVK?  If so, how?  It's unclear if I got something wrong with the "dd" command, or am trying to use the wrong file.

[tomsong]

Hi,

     Could somebody help to explain the following command:

      sudo dd if=u-boot.img of=/dev/mmcblk0 bs=1k seek=69

      Why seek=69? Can this value be changed and where is it defined?

      Thanks!

[Carlos_Musich · Accepted solution]

Hi Nick,

In In the tmp/deploy/images/imx6ulevk/ you can find a .sdcard file. It contains the full image (kernel, device tree, root file system and u-boot). You can use this file with the next command

$ sudo dd if=<fileName>.sdcard of=/dev/<sdcardUnit> bs=1M && sync

Please check Task #4 in Yocto Training - HOME 

to deploy just u-boot you may use the following commands:

$ sudo dd if=SPL of=/dev/mmcblk0 bs=1k seek=1
$ sudo dd if=u-boot.img of=/dev/mmcblk0 bs=1k seek=69

Regards,
Carlos
NXP Technical Support
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[nickbedbury]

The SPL and u-boot.img commands you referenced do work.

I also was able to use:

   sudo dd if=u-boot.imx of=/dev/mmcblk0 bs=1k seek=1

with the 2017.03 u-boot revision