When a network boot is performed with the U-boot net_boot command, the OnSite boots from the specified image on the specified TFTP server. The image uses the RAMDISK as the root file system. Network boots are useful for troubleshooting because the net-booted image can run even if the OnSite’s flash memory is not usable.Network boots are recommended only for troubleshooting and must not be used for normal operation of the OnSite. For example, if you want to test a new release of the software to make sure a problem is fixed, or if the resident flash memory becomes corrupted, you could download the software from a tftpboot server, and then save it to the removable flash after testing, using the create_cf command with the appropriate options (see Options for the create_cf Command).When a network boot is performed, the system uses one of the two following sources of configuration data:
• If the net_boot command is entered with the configsource=factory_default option, the factory_default configuration files are restored.
• Otherwise, the backed up configuration files from the /dev/hda3 backup partition are copied to the RAMDISK and used.Any configuration changes made after the last backup copy was made are lost unless the configuration files were backed up before the network boot and then restored afterwards (see How Configuration Files Changes Are Managed).To Replace a Boot Image From a Network Boot in U-Boot Monitor Mode
2. Set the “bootfile,” “serverip,” and “ipaddr” environment variables using the boot filename, the TFTP boot server’s IP address, and the IP address of the OnSite to use for network booting.
The format of the boot filename is: zmppcons.vversion_number, for example: zmppcons.v110. See the following screen example.
3. Check that the environment variables are set properly with the printenv command.
4. Enter the net_boot command.
=> net_boot
6.
[root@OnSite root]# create_cf --doformat --factory_defaultNote: Be aware that the --doformat option erases the flash memory and installs the boot image into the image1 area. See Options for the create_cf Command for other options.
Creation of image N completed.
9. Enter the reboot command.
# reboot