Bootloader Shell Options; Table 4-3: Bootloader Environment Variables - Kontron CP6924-1 User Manual

4.3.2

Bootloader Shell Options

The boot process can be interrupted by entering the bootstopkey phrase "stop". This will open a bootloader shell session.
Entering "?" provides a list of possible built-in commands, "printenv" provides a list of current environment settings. The
bootloader shell can be used to customize boot options and system startup by changing some of its environment variables.
A list of available environment variables and its description can be seen in the table below.
Table 4-3:
Bootloader Environment Variables
Name
baudrate
bootargs
bootcmd
bootcmdcli
bootcmdflash
bootcmdnet
bootcmdprd
bootcmdrecovery
bootcmdrollback
check bootsource
check rollback
bootdelay
bootsource
bootstopkey
check bootsource
check rollback
clear_conf ig
clear_env
disable_rollback
ethact
56
Type
Serial line baudrate
Var
default: 115200
Default kernel arguments. (quiet postresult=0x${postresult}
Var
${vram_kinfo})
This variable def ines a command string that is automatically executed
when the initial countdown is not interrupted.
Script
This command is only executed when the variable bootdelay is also
def ined!
contains startup script which will drop to CLI and wait. This is used in
Script case that the system detects a rollback failed condition (rollback_ctl
= 1).
contains the standard startup script for loading OS image from flash
Script partition command. This will load the Linux kernel and start it with a
INITRD type root f ile system.
contains the standard startup script for loading OS image from net-
Script
work.
Script contains the standard startup script for use during board production.
contains standard startup script for board f irmware recovery in boot
Script
f irmware.
contains standard startup script for board f irmware rollback from
Script
backup partition af ter a CRC checksum error has been detected.
Script check for user def ined bootcmd/bootargs pair.
Script check whether previous rollback failed and drop into bootloader CLI.
Af ter reset, U-Boot will wait this number of seconds before it executes
the contents of the bootcmd variable. During this time a countdown is
printed, which can be interrupted by pressing any key.
Set this variable to 0 boots without delay. Be careful: depending on
the contents of your bootcmd variable, this can prevent you from
Var
entering interactive commands again forever!
Set this variable to -1 to disable autoboot.
default: 3 for boot monitor, 10 for boot write-protected boot f irm-
ware.
When the standard boot sequence is used, contains the boot source,
either flash, net, prd to select the respective boot sequence to acti-
vate. It is only used when bootcmd contains the default startup
Var
script, which may be overridden by the user.
default: flash
Def ines the key phrase that the user needs to type to drop into the
bootloader command line interface during startup.
Var
not set – use string "stop" as bootstop key phrase (default)
<any> - use string <any> as bootstop key phrase
Script Check for user def ined bootsource extensions and execute them
Script Check for rollback prerequisites and start 'run rollback_flash' script
Erase conf ig partition to restore factory defaults for Linux BSP set-
Script
tings.
Script Erase U-Boot environment sectors.
0 – rollback when CRC check of kernel or rootfs fails (default)
Var
1 – do not rollback
Default network interface used by network commands (bootp, tf tp-
boot et al)
Var
default: ppc_4xx_eth0
CP6924-1 User Guide
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