mx6sabreauto

How to use and build U-Boot on mx6sabreauto

mx6sabreauto_defconfig target supports mx6q/mx6dl/mx6qp sabreauto variants.

In order to build it:

$ make mx6sabreauto_defconfig
$ make

This will generate the SPL and u-boot-dtb.img binaries.

  • Flash the SPL binary into the SD card:
$ sudo dd if=SPL of=/dev/sdX bs=1K seek=1 conv=notrunc && sync
  • Flash the u-boot-dtb.img binary into the SD card:
$ sudo dd if=u-boot-dtb.img of=/dev/sdX bs=1K seek=69 conv=notrunc && sync

Booting via Falcon mode

Write in mx6sabreauto_defconfig the following define below:

CONFIG_SPL_OS_BOOT=y

In order to build it:

$ make mx6sabreauto_defconfig
$ make

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

  • Flash the SPL image into the SD card:
$ sudo dd if=SPL of=/dev/sdb bs=1K seek=1 conv=notrunc && sync
  • Flash the u-boot-dtb.img image into the SD card:
$ sudo dd if=u-boot-dtb.img of=/dev/sdb bs=1K seek=69 conv=notrunc && sync

Create a FAT16 boot partition to store uImage and the dtb file, then copy the files there:

$ sudo cp uImage /media/boot
$ sudo cp imx6dl-sabreauto.dtb /media/boot

Create a partition for root file system and extract it there:

$ sudo tar xvf rootfs.tar.gz -C /media/root

The SD card must have enough space for raw “args” and “kernel”. To configure Falcon mode for the first time, on U-Boot do the following commands:

  • Load dtb file from boot partition:

    # load mmc 0:1 ${fdt_addr} imx6dl-sabreauto.dtb
    
  • Load kernel image from boot partition:

    # load mmc 0:1 ${loadaddr} uImage
    
  • Write kernel at 2MB offset:

    # mmc write ${loadaddr} 0x1000 0x4000
    
  • Setup kernel bootargs:

    # setenv bootargs "console=ttymxc3,115200 root=/dev/mmcblk0p1 rootfstype=ext4 rootwait quiet rw"
    
  • Prepare args:

    # spl export fdt ${loadaddr} - ${fdt_addr}
    
  • Write args 1MB data (0x800 sectors) to 1MB offset (0x800 sectors):

    # mmc write 18000000 0x800 0x800
    
  • Restart the board and then SPL binary will launch the kernel directly.