The common CFI driver provides this weak default implementation for flash_cmd_reset(): void __flash_cmd_reset(flash_info_t *info) { /* * We do not yet know what kind of commandset to use, so we issue * the reset command in both Intel and AMD variants, in the hope * that AMD flash roms ignore the Intel command. */ flash_write_cmd(info, 0, 0, AMD_CMD_RESET); flash_write_cmd(info, 0, 0, FLASH_CMD_RESET); } void flash_cmd_reset(flash_info_t *info) __attribute__((weak,alias("__flash_cmd_reset"))); Some flash chips seems to have trouble with this reset sequence. In this case the board specific code can override this weak default version with a board specific function. For example the digsy_mtc board equipped with the M29W128GH from Numonyx needs this version to function properly: void flash_cmd_reset(flash_info_t *info) { flash_write_cmd(info, 0, 0, AMD_CMD_RESET); } see also: http://www.mail-archive.com/u-boot@lists.denx.de/msg24368.html Config Option CONFIG_SYS_MAX_FLASH_SECT: Number of sectors available on Flash device CONFIG_SYS_FLASH_CFI_WIDTH: Data-width of the flash device CONFIG_CMD_FLASH: Enables Flash command library CONFIG_FLASH_CFI_DRIVER: Enables CFI Flash driver CONFIG_FLASH_CFI_MTD: Enables MTD frame work for NOR Flash devices