英伟达Xavier NX 开发系列之如何烧录l4t_initrd.img

修复开机时文件系统无法挂载的问题： “ERROR: mmcblk0p1 mount fail” boot up error

因为Nvidia jetson系列定位为嵌入式产品，设计上很多都不是带电池的，有不少产品在关机的时候都是直接断电，时间长了容易在开机的时候出现，“ERROR: mmcblk0p1 mount fail”文件系统无法正常挂载的问题，那么如何修复此问题呢？

解决方案：在l4t_initrd.img加入e2fsck, 通过e2fsck实现e2fsck /dev/mmcblk0p1文件系统的校验，使系统能正常boot up

先科普几个说明：

l4t_initrd.img： 初始 RAM 磁盘（initrd）映像，
l4t_initrd_flash.sh： 是一个用于烧录 Nvidia Jetson 设备的脚本， 烧录初始 RAM 磁盘（initrd）映像到 Jetson 设备的脚步，用于恢复初始 RAM 磁盘（initrd）
README_initrd_flash.txt： 通常是伴随着 Nvidia Jetson 系列设备的一个文本文件，它包含了关于如何使用 l4t_initrd_flash.sh 

那么正常的nvidia系统l4t_initrd.img中是没有自带e2fsck，需要做的是往l4t_initrd.img加入e2fsck，具体操作如下：

如何修改l4t_initrd.img，并且打包l4t_initrd.img映像：

Modifying Jetson RAM Disk
Use the following procedure to modify the default configuration of a Jetson device’s RAM disk.
To modify RAM disk
1.Unpack your initrd:
$ sudo su
$ cp /boot/initrd /tmp
$ mkdir /tmp/temp
$ cd /tmp/temp
$ gunzip -c /tmp/initrd | cpio -i
2.Modify your initrd content in the tmp/temp/ folder:
3.Package your initrd:
$ sudo su
$ cd /tmp/temp
$ find . | cpio -H newc -o | gzip -9 -n > ../initrd
4.Replace the initrd with your customized initrd:
$ cp /tmp/initrd /boot/initrd
$ cp /tmp/initrd /boot/initrd

 实操demo：

 将旧的l4t_initrd.img备份，新的my_l4t_initrd.img重命名替换旧的，然后将之烧录jetson设备上

那么下一步如何烧录l4t_initrd.img？

实际：yahboom@yahboom-vm:~/jetsonNX_r32.7.2/Linux_for_Tegra$   ./tools/kernel_flash/l4t_initrd_flash.sh  --flash-only   --initrd  --showlogs  jetson-xavier-nx-devkit-emmc  mmcblk0p1

备注： --flash-only       //Flash using existing images //烧录存在l4t_initrd.img 不重新编译

               --initrd   //Stop after device boot into initrd.  //进入recovery模式后，停止设备进入 initrd

            --showlogs    // Spawn gnome-terminal to show individual flash process logs. Applicable
                               //  for --massflash only. 显示一些log信息信息

相关信息：

yahboom@yahboom-vm:~/jetsonNX_r32.7.2/Linux_for_Tegra$ ./tools/kernel_flash/l4t_initrd_flash.sh  --help

Usage: ./tools/kernel_flash/l4t_initrd_flash.sh <options> <board-name> <rootdev>
Where,
    -u <PKC key file>            PKC key used for odm fused board.
    -v <SBK key file>            SBK key used for encryptions
    -p <option>                  Pass options to flash.sh when generating the image for internal storage
    -k <target_partition>        Only flash parition specified with the label <target_partition>
    <board-name>                 Indicate which board to use.
    <rootdev>                    Indicate what root device to use
    --no-flash                   Generate the flash images
    --flash-only                 Flash using existing images
    --external-device <dev>      Generate and/or flash images for the indicated external storage
                                 device. If this is used, -c option must be specified.
    --external-only              Skip generating internal storage images
    --usb-instance               Specify the usb port where the flashing cable is plugged (i.e 1-3)
    --sparse                     Use sparse image to flash instead of tar image.
    -c <config file>             The partition layout for the external storage device.
    -S <size>                    External APP partition size in bytes. KiB, MiB, GiB short hands are allowed,
                                 for example, 1GiB means 1024 * 1024 * 1024 bytes. (optional)
    --massflash [<max_devices>]  Flash multiple device. Receive an option <count> argument to indicate the
                                 maximum number of devices supported. Default is 10 if not specified in board config file
    --showlogs                   Spawn gnome-terminal to show individual flash process logs. Applicable
                                 for --massflash only.
    --reuse                      Reuse existing working environment kept by --keep option.
    --keep                       Keep working environment instead of cleaning up after flashing
    --erase-all                  Delete all storage device before flashing
    --initrd                     Stop after device boot into initrd.
    --network <netargs>          Flash through Ethernet protocal using initrd flash. <netargs> can be "usb0" to flash through the USB Flashing cable
                                 or "eth0:<target-ip>/<subnet>:<host-ip>" to flash through the LAN cable
                                 For examples:
                                 --network usb0
                                 --network eth0:192.168.0.17/24:192.168.0.21
    --append                     Only applicable when using with --no-flash --external-only option. This option is parts of
                                 the three steps flashing process to generate images for internal device and external device seperately
                                 and flash them together.
                                 For examples:
                                1. sudo ./tools/kernel_flash/l4t_initrd_flash.sh --no-flash jetson-xavier internal
                                2. sudo ./tools/kernel_flash/l4t_initrd_flash.sh --no-flash --external-device nvme0n1p1 -S 5120000000 -c flash_enc.xml --external-only --append jetson-xavier internal
                                3. sudo ./tools/kernel_flash/l4t_initrd_flash.sh --flash-only jetson-xavier internal


With --external-device options specified, the supported values for <dev> are
    nvme0n1
    sda

Examples:
	Both external and internal flash
	sudo <BSP_TOOLS_DIR>/./tools/kernel_flash/l4t_initrd_flash.sh  -c ~/Downloads/flash_l4t_nvme.xml -S 10240000000 --external-device nvme0n1 jetson-xavier-nx-devkit-emmc external

	Internal only
	sudo <BSP_TOOLS_DIR>/./tools/kernel_flash/l4t_initrd_flash.sh  jetson-xavier-nx-devkit-emmc mmcblk0p1


	External only:
	sudo <BSP_TOOLS_DIR>/./tools/kernel_flash/l4t_initrd_flash.sh  --external-only -c ~/Downloads/flash_l4t_nvme.xml -S 10240000000 --external-device nvme0n1 jetson-xavier-nx-devkit-emmc external