3.1 Compiling U-Boot
Enter Bootloader directory, extract U-boot source tar ball:
cd $DEV_ROOT/04-Source
tar -xvf MYiR-iMX-uboot.tar.gz
cd MYiR-iMX-uboot
Compiling：
make distclean
make <config>
make
The
| Boot Mode | Config file |
|---|---|
| MYS-6ULX-IND NAND Flash | mys_imx6ul_14x14_nand_defconfig |
| MYS-6ULX-IND eMMC Flash | mys_imx6ul_14x14_emmc_defconfig |
| MYS-6ULX-IoT NAND Flash | mys_imx6ull_14x14_nand_defconfig |
| MYS-6ULX-IoT eMMC Flash | mys_imx6ull_14x14_emmc_defconfig |
U-Boot will search and execute a script file "boot.scr" when U-Boot booting up. It used to change boot type in temporary.Next is use "mys-imx6ul-boot-sdcard.txt" to generate the "boot.scr" file as example. The mkimage tool source code is locate in "U-Boot/tools" directory. It will be compiled after U-Boot compiled.
cat mys-imx6ul-boot-sdcard.txt
setenv mmcroot '/dev/mmcblk0p2 rootwait rw rootdelay=5 mem=256M'
setenv mmcargs 'setenv bootargs console=${console},${baudrate} \
root=${mmcroot} mtdparts=gpmi-nand:5m(boot),10m(kernel),\
1m(dtb),-(rootfs)'
run mmcargs
fatload mmc 0 0x83000000 zImage
fatload mmc 0 0x84000000 mys-imx6ul-14x14-evk-emmc.dtb
bootz 0x83000000 - 0x84000000
./tool/mkimage -A arm -T script -O linux \
-d mys-imx6ul-boot-sdcard.txt boot.scr