修改：

tools/firmware-utils/src/mktplinkfw2.c

static struct flash_layout layouts[] = {

	{

		.id		= "8Mltq",

		.fw_max_len	= 0x7a0000,

		.kernel_la	= 0x80002000,

		.kernel_ep	= 0x80002000,

		.rootfs_ofs	= 0x140000,

	}, {

		.id		= "12Mmtk",//这里改了

		.fw_max_len	= 0xC00000,

		.kernel_la	= 0x80000000,

		.kernel_ep	= 0x80000000,

		.rootfs_ofs	= 0x140000,

	}, {

		/* terminating entry */

	}

};

static struct board_info boards[] = {

	{

		.id		= "TD-W8970v1",

		.hw_id		= 0x89700001,

		.hw_rev		= 1,

		.layout_id	= "8Mltq",

	}, {

		.id		= "ArcherC20i",

		.hw_id		= 0xc2000001,

		.hw_rev		= 58,

		.layout_id	= "12Mmtk",//这里改了

		.hdr_ver	= 3,

		.endian_swap	= true,

	}, {

		/* terminating entry */

	}

};

过程：首先grep搜索这个错误，有好几个文件有，修改每一个，把文件名打印出来（其实报错的时候有提示文件名，我没注意）；

然后把相关的数字、字符打印出来：

ERR("rootfs image is too big from -> mktplinkfw2.c board_id=%s, layout_id=%s, layout->fw_max_len=%d", board_id, layout_id,layout->fw_max_len);

编译一次，我就知道解决方法了，