System information

U-Boot Network Boot Options and Caveats
414 AlterPath OnBoard Administrator’s Guide
U-Boot Network Boot Options and Caveats
When a network boot is performed with the U-boot net_boot command,
the OnBoard boots from the specified image on the TFTP server. The image
uses the RAM as the root file system. Network boots are useful for
troubleshooting because the net-booted image can run even if there the
OnBoard’s flash memory is not usable.
Network boots are recommended only for troubleshooting and must not be
used for normal operation of the OnBoard. For example, if you want to test a
new release of the software to make sure a problem is fixed, or if the
removable flash memory becomes corrupted, you could download the
software to 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” on page 416).
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 “Backing Up Configuration Files” on page 100
and “Restoring Backed Up Configuration Files” on page 100).
T To Upgrade to a Boot Image From a Network
Boot in U-Boot Monitor Mode
Before performing this procedure, make sure that a copy of the latest boot
image has been downloaded from the Cyclades ftp site
(ftp.cyclades.com/pub/cyclades/alterpath/onboard/
released) to a TFTP server that is accessible to the OnBoard.
1. Log in as root and go to U-boot monitor mode.
If needed, see ‘“To Boot in U-Boot Monitor Mode” on page 412.