修改分区大小

i2S-6UB NAND版本的默认分区方案如下，默认NAND Flash为256MB。

mtdparts=mtdparts=gpmi-nand:5m(bootloader),1m(env),1m(safe),16m(linux),32m(recovery),150m(rootfs),-(data)

开发者需要调整分区时，可以修改U-Boot的include/configs/i2s6ull_common.h文件中的MTDPARTS_256MB宏定义：

375 #define MTDPARTS_256MB                  "mtdparts=" CONFIG_NAND_NAME ":" \
376                                         "5m(" CONFIG_UBOOT_PARTITION ")," \
377                                         "1m(env)," \
378                                         "1m(safe)," \
379                                         "16m(" CONFIG_LINUX_PARTITION ")," \
380                                         "32m(" CONFIG_RECOVERY_PARTITION ")," \
381                                         "150m(rootfs)," \
382                                         "-(data)"

修改后同时也要修改mtdrootfspart和mtdrootfsidx的宏定义，用于确定从哪个分区来加载rootfs。

371 #define CONFIG_ROOTFS_PARTITION         "rootfs"

393 #define CONFIG_ENV_MTD_ROOTFS_INDEX     "5"