看一下openWRT配置，在根目录执行make menuconfig，搜索redund看看

Symbol: SUNXI_MAKE_REDUNDANT_ENV [=y] │ │ Type : bool │ │ Defined at target/linux/generic/image/Config.in:223 │ │ Prompt: sunxi make redundant env data │ │ Location: │ │ (1) -> Target Images │ │ │ │ │ │ Symbol: SUNXI_REDUNDANT_ENV_SIZE [=0x20000] │ │ Type : string │ │ Defined at target/linux/generic/image/Config.in:229 │ │ Prompt: redundant env data size │ │ Depends on: SUNXI_MAKE_REDUNDANT_ENV [=y] │ │ Location: │ │ -> Target Images │ │ (2) -> sunxi make redundant env data (SUNXI_MAKE_REDUNDANT_ENV [=y])