imx6ull EMMC和NABD 的移植注意事项，差别

移植时使用emmc的dtb设备树文件使用网络文件系统、tftp方式加载内核文件和设备树文件没有问题，这时候在网络文件系统内使用   cat /proc/mtd   不可以查看分区情况 ，

下载到nand后，系统不可以启动，显示读取内核文件失败和读取设树文件失败；

问题原因时，nand 的驱动没有开启，需要新建一个nand的设备dts文件

 文件内容如下：

/*
 * Copyright (C) 2016 Freescale Semiconductor, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include "imx6ull-alientek-emmc.dts"

&gpmi {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_gpmi_nand_1>;
	status = "okay";
	nand-on-flash-bbt;
};

&iomuxc {
	imx6ull-evk-gpmi-rework {
		pinctrl_gpmi_nand_1: gpmi-nand-1 {
			fsl,pins = <
				MX6UL_PAD_NAND_CLE__RAWNAND_CLE         0xb0b1
				MX6UL_PAD_NAND_ALE__RAWNAND_ALE         0xb0b1
				MX6UL_PAD_NAND_WP_B__RAWNAND_WP_B       0xb0b1
				MX6UL_PAD_NAND_READY_B__RAWNAND_READY_B 0xb000
				MX6UL_PAD_NAND_CE0_B__RAWNAND_CE0_B     0xb0b1
				MX6UL_PAD_NAND_CE1_B__RAWNAND_CE1_B     0xb0b1
				MX6UL_PAD_NAND_RE_B__RAWNAND_RE_B       0xb0b1
				MX6UL_PAD_NAND_WE_B__RAWNAND_WE_B       0xb0b1
				MX6UL_PAD_NAND_DATA00__RAWNAND_DATA00   0xb0b1
				MX6UL_PAD_NAND_DATA01__RAWNAND_DATA01   0xb0b1
				MX6UL_PAD_NAND_DATA02__RAWNAND_DATA02   0xb0b1
				MX6UL_PAD_NAND_DATA03__RAWNAND_DATA03   0xb0b1
				MX6UL_PAD_NAND_DATA04__RAWNAND_DATA04   0xb0b1
				MX6UL_PAD_NAND_DATA05__RAWNAND_DATA05   0xb0b1
				MX6UL_PAD_NAND_DATA06__RAWNAND_DATA06   0xb0b1
				MX6UL_PAD_NAND_DATA07__RAWNAND_DATA07   0xb0b1
			>;
		};
	};
};

&qspi {
	status = "disabled";
};

&usdhc2 {
	status = "disabled";
};

打开makefile文件：