How to use and build U-Boot on mx6sabreauto
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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.img binaries.
- Flash the SPL binary into the SD card:
$ sudo dd if=SPL of=/dev/sdX bs=1K seek=1 && sync
- Flash the u-boot.img binary into the SD card:
$ sudo dd if=u-boot.img of=/dev/sdX bs=1K seek=69 && sync
Booting via Falcon mode
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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.img.
- Flash the SPL image into the SD card:
$ sudo dd if=SPL of=/dev/sdb bs=1K seek=1 && sync
- Flash the u-boot.img image into the SD card:
$ sudo dd if=u-boot.img of=/dev/sdb bs=1K seek=69 && 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.
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