Freescale ARM iMX53 Startup


Introduction

This document will describe in detail the procedures for booting a Linux kernel image and mounting a root file system over nfs on the Freescale i.MX53 Quick Start Board.

Prerequisites

Host Requirements

To properly boot a board using software from Timesys, your host machine must meet the following requirements:
  • Modern GNU/Linux Distribution. While you can use nearly any modern Linux distribution released in the last 24 months, Timesys recommends one of the following:
    • Ubuntu (Most recent release or LTS)
    • Fedora (Most recent release)
  • An internet connection on the Development Host.
  • Root or sudo permission on the Development Host.
  • A copy of the Linux Kernel ( uImage) and Root File System (rootfs.tar.gz) for the Target Board downloaded from Factory. These are found in the output directory of your online build, or in the directory build_armv7l-timesys-linux-/images/ on the command line.
  • If you are booting your root file system over the network, you will need two network cards installed and configured in the Development Host. One to communicate normally with your LAN/WAN while installing host packages, the other to communicate solely with the target board.
  • An available serial port on your Development Host.

Target Requirements

To boot the Freescale i.MX53 Quick Start Boardusing NFS (network filesystem), you will need the following items:

  • Freescale i.MX53 Quick Start Board
  • 5V Power Supply
  • RS232 Serial Cable
  • Ethernet Crossover Cable or Ethernet hub/switch and Ethernet Patch Cables
  • microSD card (comes with i.MX53 QSB)
Once you have all of the necessary components, you should perform the following steps:

  1. Connect the UART port of the MX53 board to the serial port of your workstation using the RS232 serial cable.
  2. If you are using a cross-over cable, connect the Ethernet port of the EVK board to the second Ethernet port of your workstation.
  3. If you are using an Ethernet hub or switch, connect the debug board to the hub with a straight-through Ethernet cable, then connect the hub to the second Ethernet port of your workstation.
  4. Connect the power supply to your board.

Preparing the Target

Loading U-Boot to microSD

The microSD card that comes with the i.MX53 QSB is pre-loaded with U-Boot. To install a new Timesys build of the bootloader onto the microSD, follow these directions: Note The following instructions will overwrite data on your microSD. Make sure to back up any valuable data before performing this operation.
  1. From the host, run:
    ls /dev/sd*
    Note which memory devices are currently connected to your computer. We will use this information to determine the microSD device name.
  2. Connect the microSD card to your host, via a microSD slot, an SD card adapter, or a USB adapter. Note: the SD card adapter that comes with the i.MX53 QSB may not allow you to write to your microSD card. In this case, seek another method of connection to the host.
  3. Find the microSD device name. From the host, run:
    ls /dev/sd*
    The name of your microSD device is a variant of /dev/sdX where X is an alphabetic letter. Your device name is the device which appeared in the second call to ls but not the first. Note: It is important that correctly identify the microSD device; otherwise you will corrupt the data on another device attached to your host
  4. Unmount all partitions on the microSD. With root permissions, run:
    umount /dev/sdX*
    where /dev/sdX is the device name found in the previous step.
  5. Load U-Boot to the microSD device. To load Timesys U-Boot to the microSD, run the following command with root permissions:
    dd if=/path/to/factory/ build_armv7l-timesys-linux-/images/\
            bootloader/u-boot.bin of=/dev/sdX bs=512 seek=1 skip=1
    Even though the string following if is broken here with a backslash for formatting purposes, the string following if should be a single spaceless string without a backslash representing the full path to you U-Boot binary. Substitute /path/to/factory/ with the path to your factory and /dev/sdX with the microSD device name. This command loads U-Boot to a 512-byte offset on the microSD, skipping the first 512-bytes of the U-Boot binary, which is blank. The skip and seek ensures the partition table is not overwritten by the bootloader.
  6. Call:
    sync
    to flush the output buffer
Remove the microSD from your host, and slide it into the slot of your i.MX53 QSB. You should hear the card 'click' into place. Once the power supply is connected, press the 'POWER' button in the bottom left corner of the board to boot the board. The LEDs in the same corner will shine bright blue and green to show that the board is booting.

Configuring Serial Communication

The i.MX53 QSB uses a serial debug port to communicate with the host machine.
The commands discussed in this section are meant to be performed by a privileged user account. This requires the root login or prepending each command with sudo.

Using Minicom


  1. Start minicom on your host machine in configuration mode. As root:
    # minicom -o -s -w
  2. A menu of configuration should appear. Use the Down-arrow key to scroll down and select the Serial port setup option, and press Enter.
  3. Verify that the listed serial port is the same one that is connected to the target board. If it is not, press A, and enter the correct device. This is /dev/ttyS0 on most Linux distributions.
  4. Set the Bps/Par/Bits option by pressing the letter E and using the next menu to set the appropriate values. You press the key that corresponds to the value 115200, then press Enter.
  5. Set Hardware flow control to No using the F key.
  6. Set Software flow control to No using the G key.
  7. Press Enter to return to the main configuration menu, and then press Esc to exit this menu.
  8. Reset the board, and wait for a moment. If you do not see output from the board, press Enter several times until you see the prompt. If you do not see any output from the board, and have verified that the serial terminal connection is setup correctly, contact your board vendor.
TIP: If you experience an error similar to Device /dev/ttyS0 is locked when starting minicom, it usually means that another process is using the serial port (which is usually another instance of minicom). You can find the process that is currently using the serial port by executing the following:

# fuser /dev/ttyS0
/dev/ttyS0:         28358

# ps 28358
  PID TTY      STAT  TIME COMMAND
  28923 pts/0    S+    0:00 minicom
This process can also be killed directly with fuser as root. Please use this command with caution:

# fuser -k /dev/ttyS0

Using GNU Screen

To quickly connect to a board using Gnu Screen, execute the following:

# screen /dev/ttyS0 115200
For more information about using screen, please consult the man page, or view the manual online at http://www.gnu.org/software/screen/manual/screen.html



Configuring the Network Interface


Finding and Changing the MAC Address

The MAC address on the i.MX53 QSB is set by the ethaddr environment variable in U-Boot.
If ethaddr is not set, it can be set using the setenv command.
Example

> setenv ethaddr 12:34:56:78:9a:bc
The MAC Address can be found using the printenv command in U-Boot.
Example

> printenv
baudrate=115200
bootfile="uImage"
stdin=serial
stdout=serial
stderr=serial
ethaddr=12:34:56:78:9a:bc
NOTE Once the MAC address has been set, it cannot be changed without destroying the entire U-Boot environment.

Changing the IP Address

The IP address can be set manually by modifying the ipaddr environment variable, or automatically using the dhcp or bootp commands.

Preparing the Host


Setting up the network

The commands discussed in this section are meant to be performed by a privileged user account. This requires the root login or prepending each command with sudo.

Identify the network adapter connecting the Host to the Target

Timesys only supports direct Ethernet connections from the development Host to the Target board. Ideally, the development Host would have two network adapters; one adapter to connect to your LAN, and one Ethernet card to connect directly to the Target board with a crossover cable or Ethernet hub. If your development Host only has one network interface it must be directly connected to the Target board.
The Ethernet adapter connected directly to the target board must be:
  • Configured with a proper static IP address and Subnet Mask.
  • Connected directly to the target board with either a crossover cable or its own Ethernet hub.
From a command prompt issue the command:

# /sbin/ifconfig
Each interface will report its IP address, Subnet Mask, and Default Gateway information:

eth0 Link encap:Ethernet HWaddr 00:19:bb:49:ff:0e      
        inet addr:192.168.3.244 Bcast:192.168.3.255 Mask:255.255.254.0
        inet6 addr: fe80::219:bbff:fe49:ff0e/64 Scope:Link      
        UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1      
        RX packets:57214 errors:0 dropped:0 overruns:0 frame:0      
        TX packets:47272 errors:0 dropped:0 overruns:0 carrier:0
        collisions:0 txqueuelen:1000      
        RX bytes:43109083 (41.1 MB) TX bytes:6308206 (6.0 MB)
        Interrupt:16
eth1 Link encap:Ethernet HWaddr 00:10:b5:4a:c1:a9      
        inet addr:10.0.0.1 Bcast:10.0.0.255 Mask:255.0.0.0      
        UP BROADCAST MULTICAST MTU:1500 Metric:1      
        RX packets:0 errors:0 dropped:0 overruns:0 frame:0      
        TX packets:0 errors:0 dropped:0 overruns:0 carrier:0     
        collisions:0 txqueuelen:1000      
        RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)      
        Interrupt:21 Base address:0x1100
lo  Link encap:Local Loopback      
        inet addr:127.0.0.1 Mask:255.0.0.0      
        inet6 addr: ::1/128 Scope:Host      
        UP LOOPBACK RUNNING MTU:16436 Metric:1      
        RX packets:1974 errors:0 dropped:0 overruns:0 frame:0      
        TX packets:1974 errors:0 dropped:0 overruns:0 carrier:0     
        collisions:0 txqueuelen:0      
        RX bytes:226637 (221.3 KB) TX bytes:226637 (221.3 KB)
Note the IP address and Subnet Mask of the appropriate network connection. You will use this to configure the DHCP server.

Installing the server daemons on the development host


  • On Ubuntu 11.04 and newer:
    # apt-get install xinetd tftp tftpd isc-dhcp-server \
                      nfs-kernel-server portmap
  • On Ubuntu 10.11 and older:
    # apt-get install xinetd tftp tftpd dhcp3-server \
                      nfs-kernel-server portmap
    NOTE: Older versions of Ubuntu use nfs-common and nfs-user-server in place of nfs-kernel-server
  • On Fedora Core:
    # yum install xinetd tftp tftp-server dhcp nfs-utils
Important:
After installing these packages the DHCP server software may start automatically. Having the DHCP server running while you are connected to a LAN can interfere with the operation of other computers. After the DHCP service installs and starts issue these commands to stop the DHCP service and prevent it from starting automatically at boot:

  • To stop the dhcp service:
    • On Ubuntu 11.04 and newer:
      # service isc-dhcp-server stop
    • On Ubuntu 10.11 and older:
      # service dhcp3-server stop
    • On Fedora Core:
      # /etc/init.d/dhcp stop
  • To prevent the service from starting automatically:
    • On Ubuntu 11.04 and newer:
      # chmod 644 /etc/init.d/isc-dhcp-server
    • On Ubuntu 10.11 and older:
      # chmod 644 /etc/init.d/dhcp3-server
    • On Fedora Core:
      1. Click the System Menu
      2. Select Administration
      3. Select Services
      4. Select dhcpd
      5. Click the Customize button
      6. Uncheck Runlevel 2, 3, 4 and 5

Disable SELinux and Firewall on Fedora Core

On Fedora Core, SELinux and the firewall will interfere with many of the services that are needed to work with the target board. These should be disabled before continuing.
Generally Ubuntu does not have these services running by default.

  1. Disable SELinux:
    1. Click the System Menu
    2. Select Administration
    3. Select SELinux Management
    4. Change System Default Enforcing Mode to Disabled
  2. Disable Firewall:
    1. Click the System Menu
    2. Select Administration
    3. Select Services
    4. Select iptables
    5. Click the Customize button
    6. uncheck Runlevel 2, 3, 4 and 5

Setting up DHCP


  1. Edit the dhcpd configuration file:
    • On Ubuntu, edit /etc/dhcp/dhcpd.conf and include the following lines (note: on older versions of Ubuntu this file is at either /etc/dhcp3/dhcpd.conf or /etc/dhcpd.conf):
      subnet 10.0.0.0 netmask 255.0.0.0 {
       host targetboard {
        fixed-address 10.0.0.10;
        hardware ethernet 12:34:56:78:9a:bc;
        option root-path "/full/path/to/rfs";
        filename " uImage";
       }
      }
    • On Fedora Core, edit /etc/dhcpd.conf and include the following lines:
      ddns-update-style ad-hoc;
      subnet 10.0.0.0 netmask 255.0.0.0 {
       host targetboard {
        fixed-address 10.0.0.10;
        hardware ethernet 12:34:56:78:9a:bc;
        option root-path "/full/path/to/rfs";
        next-server 10.0.0.1;
        filename " uImage";
       }
      }
  2. Test the DHCP server on the network card that is connected to your development board. For this example assume eth1. This command will start the DHCP server in the foreground and output any status or error messages to the screen.
    • On Ubuntu:
      # service dhcp3-server restart
    • On Fedora Core:
      # /usr/sbin/dhcpd -d eth1
    • It is recommended to start the DHCP server in this manner each time you need to boot your Target board.

Setting up TFTP


  1. Edit the xinetd.conf file
    • On Ubuntu, edit /etc/xinetd.conf and add the following lines just above the line that reads includedir /etc/xinetd.d.
      service tftp
      {
       socket_type = dgram
       protocol = udp
       wait = yes
       user = root
       server = /usr/sbin/in.tftpd
       server_args = -s /tftpboot
       disable = no
      }
    • On Fedora Core, the tftp-server package creates a /etc/xinetd.d/tftp file. Edit this file and change the disable line from yes to no. The contents of the file are:
      service tftp
      {
       socket_type     = dgram
       protocol      = udp
       wait       = yes
       user       = root
       server       = /usr/sbin/in.tftpd
       server_args     = -s /tftpboot
       disable      = no
       per_source      = 11
       cps       = 100 2
       flags       = IPv4
      }
  2. Create the /tftpboot folder if it does not exist:
    # mkdir /tftpboot
  3. Copy the kernel image to the /tftpboot directory:
    # cp /path/to/kernel/image/uImage \
                      /tftpboot/uImage
    NOTE Also copy other files that are required for booting, such as a device tree blob, to /tftpboot.
  4. Restart the xinetd server with the following command:
    # /etc/init.d/xinetd restart
  5. Test the TFTP server with the following commands
    # tftp localhost
    tftp> get  uImage
    Received 1456898 bytes in 0.4 seconds
    tftp> quit
  6. Set xinetd to start automatically on Fedora Core. Ubuntu users will skip this step.
    1. Click the System Menu
    2. Select Administration
    3. Select Services
    4. Select xinetd
    5. Click the Customize button
    6. Check Runlevel 2, 3, 4 and 5

Setting up NFS


  1. As root, extract rootfs.tar.gz to a directory and note the path. This path will be referred to as /full/path/to/rfs in this document.
    # mkdir /full/path/to/rfs
    # cd /full/path/to/rfs
    # sudo tar xvf rootfs.tar.gz
  2. Export this path by editing /etc/exports to include a line similar to the following:
    /full/path/to/rfs 10.0.0.10(rw,no_root_squash)
  3. Restart the NFS services
    • On Ubuntu issue the following commands in order:
      # service portmap stop
      # service nfs-kernel-server stop
      # service portmap start
      # service nfs-kernel-server start
      NOTE: Older versions of Ubuntu use nfs-common and nfs-user-server in place of nfs-kernel-server
    • On Fedora Core:
      # /etc/init.d/nfs restart
  4. Set nfsd to start automatically on Fedora Core. Ubuntu users will skip this step.
    1. Click the System Menu
    2. Select Administration
    3. Select Services
    4. Select nfs
    5. Click the Customize button
    6. Check Runlevel 2, 3, 4 and 5

Booting the Board


Set Environment Variables

You must set a few environment variables in order to boot the board over TFTP and DHCP. This is done with the setenv and saveenv commands in U-Boot.
On the target, set the following environment variables:
Variable Value
bootargs console=ttymxc0,115200 ip=dhcp root=/dev/nfs rw
bootcmd bootp\;bootm
loadaddr 70800000
If you are not using bootp to load the kernel, you must also specify the following values:
Variable Value
serverip 10.0.0.1
ipaddr 10.0.0.10
bootfile uImage
bootargs console=ttymxc0,115200 ip=${ipaddr} root=/dev/nfs rw nfsroot=${serverip}:/full/path/to/rfs
bootcmd tftp\;bootm 70800000
Example

> setenv bootargs console=ttymxc0,115200 ip=dhcp root=/dev/nfs rw
> setenv bootcmd bootp\;bootm
> setenv loadaddr 70800000
> saveenv

Load The Kernel

You can use bootp or tftp to load the kernel. Note that the DHCP server needs to be set up for bootp, and tftp is necessary for both.
Example

> bootp
Speed: 100, full duplex
BOOTP broadcast 1
Using eTSEC1 device
TFTP from server 10.0.0.1; our IP address is 10.0.0.10
Filename ' uImage'.
Load address: 70800000
Loading: #################################################################
         #################################################################
         ##################################################
done
Bytes transferred = 2632869 (282ca5 hex)

Boot the Kernel

The bootm command is used to boot the kernel. It loads the file that was previously uploaded using the bootp, dhcp, or tftp commands.
Example

> bootm
## Booting kernel from Legacy Image at 070800000 ...
   Image Name:   Linux-2.6.35
   Image Type:   Linux Kernel Image (gzip compressed)
   Data Size:    2632805 Bytes =  2.5 MB
   Load Address: 00000000
   Entry Point:  00000000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK

Additional Information

Displays

Note: These display settings have been tested for i.MX53 QSB revision 'DO'. Previous revisions may not recognize the SEIKO LCD and display blotchy, discolored video. See 'Video Codecs Performance by Revision' in the Timesys i.MX53 QSB Documentation on determining your boards revision and codec compatibility: https://linuxlink.timesys.com/docs/projects/fsmx53start/wiki
The i.MX53 QSB supports multiple display configurations. The displays are enabled on the kernel command line at boot time.
Configure each display with a video variable and a mxcdixfb argument in your bootargs, replacing x is a 0 or 1 to correspond the board's special video outputs, DI0 and DI1:
  • DI0 supports LCD panels (e.g. SEIKO-WVGA) or HDMI.
  • DI1 supports VGA or LDB screens. VGA may be converted to Component-Out.
The i.MX53 QSB sends a video signal to each DI output that has a video variable specified, with a maximum of one display per DI. Parameters following the mxcdixfb argument specify the color and sizing of the attached display.
Additional arguments are necessary for special output formats:
  • VGA: append vga
  • Component-Out: append tve
Although not tested here, LVDS should require an ldb argument. These arguments specify the color encoding for output, and must be set to see output.
For a full list of display formats, visit the build_armv7l-timesys-linux-/linux-2.6.35/drivers/video/mxc/ directory. Pay attention to these files:
  • tve.c: TV (Component) and VGA display formats. Do not reference vga.c for VGA.
  • ldb.c: LVDS display formats
  • mxcfb.c: generic display formats
  • Use grep in the directory for anything else
The following displays were tested by Timesys, for which examples are shown in the next two sections:
  • VGA Monitor
  • SEIKO WVGA LCD Panel
  • 1080p Component-Out (Uses VGA port with VGA-to-component adapter)

Display 0 Command Line Options


  • SEIKO-WVGA LCD panel
    video=mxcdi0fb:RGB24,SEIKO-WVGA

Display 1 Command Line Options

Append di1_primary to the video string to set the DI1 display as primary. By default, the i.MX53 QSB's primary display is DI0.
  • VGA Monitor
    video=mxcdi1fb:RGB24,VGA-SXGA vga di1_primary
    where 'SXGA' can be substituted with SVGA, XGA, SXGA, or WSXGA+, based on which of these resolutions most closely matches that your monitor's resolution.
  • 1080p TV Out
    video=mxcdi1fb:YUV444,TV-1080P30 tve di1_primary
    '1080P30' may be replaced with 720P30, 720P60, 1080I60, 1080P24, or 1080P25. The first value in this string is the resolution of your TV, and the second number is its refresh rate.

Multiple Displays

The board supports up to two display connections at a time. This can be accomplished by providing a video variable for both DI0 and DI1 on the kernel command line.
Either display can be declared as 'primary' with the dix_primary argument, where x is 0 or 1 corresponding to the DI which should recieve the primary signal. The primary display accepts the video input sent to the primary framebuffer, /dev/fb0 and an optional overlay from /dev/fb2.
By default, Display 0 is the primary display. To set Display 1 as primary, add the following option to your kernel command line:

di1_primary
Example
VGA Output of SXGA resolution (primary display), and SEIKO WVGA LCD Panel

video=mxcdi0fb:RGB24,SEIKO-WVGA video=mxcdi1fb:RGB24,VGA-SXGA vga di1_primary
If your i.MX53 QSB cannot display to two screens simultaneously, make sure to update your factory such that linux-2.6.35-mxc-ipu3-dual-display.patch is selected for building the kernel. This can be accomplished by running

make update
from within your main factory directory.

Booting from microSD

Note: This section requires you to use disk partitioning and data transfer tools to set up the microSD card. Following these instructions carelessly or without understanding them could result in permanent data loss. These instructions will overwrite data on your microSD, so back up valuable data before performing these operations.
After the following steps, your microSD card will contain:
  • Master Boot Record (MBR) (512 bytes)
  • U-Boot binary (200 KB)
  • Kernel image (3-5 MB)
  • Root filesystem (100+ MB)
U-Boot is already loaded on the card from the Preparing the Target section. We must load the filesystem and kernel to the microSD.

Partitioning the microSD

With fdisk or another partitioning tool, create a partition at a 10 MB offset from the microSD's start. This offset ensures the MBR, bootloader, and kernel are not overwritten. Allocate the rest of the card's space to the partition.
Example
An appropriate partition table for the 4GB microSD card at location /dev/sdX formatted using fdisk is shown here:

sk /dev/sdX: 3951 MB, 3951034368 bytes
122 heads, 62 sectors/track, 1020 cylinders
Units = cylinders of 7564 * 512 = 3872768 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xd7fabb64

   Device Boot      Start         End      Blocks   Id  System
   /dev/sdcX            4        1020     3846294   83  Linux

Loading filesystem to microSD

Format the filesystem partition to EXT3. For a microSD at /dev/sdX, the command reads:

mkfs.ext3 /dev/sdX1
Execute this with root privileges. Mount the partition and extract rootfs.tar.gz into the EXT3 partition with root privileges.

Loading kernel to microSD

Unmount all partitions for the microSD using root privileges:

umount /dev/sdX*
where /dev/sdX is the name of the microSD device on your host. Then load the kernel to a 1 MB offset on the microSD using root privileges:
dd if=/path/to/factory/ build_armv7l-timesys-linux-/images/\
        uImage-2.6.35-ts-armv7l of=/dev/sdX bs=1M seek=1
Even though the string following if is broken here with a backslash for formatting purposes, the string following if should be a spaceless string without a backslash representing the full path to your uImage. Substitute /path/to/factory with the path to your factory on your host, and /dev/sdX with the name of your microSD device. Then run
sync
to flush the output buffer. Remove your microSD card from the host.

Booting the Board

In U-Boot, set bootcmd to load the kernel from the hex location 0x800:

set bootcmd 'mmc read 0 0x70800000 0x800 0x2000; bootm'
Modify root in the bootargs so the filesystem is loaded from microSD's sole partition. root will read:
root=b301 rw
Example
set bootargs 'console=ttymxc0,115200 root=b301 rw'
Save your environment variables with saveenv and boot the board with boot.

Booting from SD

Note: This section requires you to use disk partitioning tools to format the SD card. Following these instructions carelessly or without understanding them could result in permanent data loss.

Partitioning the SD

Partition the card into one partition for the kernel, and one for the filesystem. Provide around 5MB for the first partition to store the kernel, and allocate the rest of the space to the second partition.
Example
An approrpriate partition table for a 4 GB SD card at location /dev/sdc formatted with fdisk is shown here:

Disk /dev/sdc: 3965 MB, 3965190144 bytes
255 heads, 63 sectors/track, 482 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xbd09e231

   Device Boot      Start         End      Blocks   Id  System
   /dev/sdc1               1           2       16033+  83  Linux
   /dev/sdc2               3         482     3855600   83  Linux

Moving Bootfiles to SD card

Format the first and second partitions to VFAT and EXT3, respectively. For an SD at /dev/sdc, this will look like:
mkfs.vfat /dev/sdc1
mkfs.ext3 /dev/sdc2
Execute the previous commands with root privileges. Mount the partitions, copy your kernel as uImage to the VFAT partition, and extract the rootfs.tar.gz into the second partition with root privileges. Unmount the SD from your host.

Booting the Board

In U-Boot, set bootcmd to boot the kernel from the SD card's VFAT partition:

set bootcmd 'mmcinfo 1; fatload mmc 1:1 0x70800000 uImage; bootm'
mmcinfo allows U-Boot to load information on the SD. Modify the root string in your bootargs so the filesystem is loaded from the SD card. The full root string will appear:
root=/dev/mmcblk1p2 rootwait rw
Example
set bootargs 'console=ttymxc0,115200 root=/dev/mmcblk1p2 \
               rootwait rw'
Save your environment variables with saveenv and boot the system with boot.

1 comment:

  1. 10.0.0.1 Login The default local address for the network router is 10.0.0.1 and this is also a “class A” internet protocol address used by the private network
    10.0.0.1 ip login

    ReplyDelete

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