Changing the storage for U-boot environment variables
U-Boot on Freescale BSP has a compiling option that allows you to choose the storage for environment variables.
1 - Extract the u-boot source using LTIB:
./ltib -m prep -p u-boot
2 - The source will be extracted to <ltib path>/rpm/BUILD/u-boot-2009.08
3 - On u-Boot source locate the i.MXEVK config file, <ltib path>/rpm/BUILD/u-boot-2009.08/include/configs/mx51_bbg.h
4 - To change the storage of variables environment to SD card, on this file, comment out CONFIG_FSL_ENV_IN_SF and define CONFIG_FSL_ENV_IN_MMC:
//#define CONFIG_FSL_ENV_IN_SF
#define CONFIG_FSL_ENV_IN_MMC
5 - Adjust CONFIG_ENV_SECT_SIZE and CONFIG_ENV_OFFSET accordingly. Recall that sd card read block size is 512B.
For example:
#define CONFIG_ENV_SECT_SIZE (256 * 512)
#define CONFIG_ENV_SIZE CONFIG_ENV_SECT_SIZE
#if defined(CONFIG_FSL_ENV_IN_MMC)
#define CONFIG_ENV_IS_IN_MMC 1 #define CONFIG_ENV_OFFSET (1023 * 512)
6 - Save the file.
7 - Recompile u-boot:
./ltib -m scbuild -p u-boot
8 - Your new compiled u-boot image will be saved at: <ltib path>/rpm/BUILD/u-boot-2009.08/u-boot.bin
