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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 Shell Options
Name
bootargs
bootcmd
bootcmdflash
bootcmdnet
bootcmdprd
bootcmdrecover
bootdelay
bootsource
bootstopkey
clear_config
clear_env
disable_rollback
Type
Var
Default kernel arguments. (mem=504M root=/dev/ram0 quiet)
This variable defines a command string that is automatically exe-
cuted when the initial countdown is not interrupted.
Script
This command is only executed when the variable bootdelay is also
defined!
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
CRAMFS (TBC, maybe INITRD) type root file 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 firmware recovery in boot
Script
firmware
After reset, U-Boot will wait this number of seconds before it exe-
cutes the contents of the bootcmd variable. During this time a count-
down 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 firm-
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
Defines 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
Erase config partition to restore factory defaults for Linux BSP set-
Script
tings.
Command script (use with "run clear_env") that erases the U-Boot
Script
environment for the active image
0 – rollback when CRC check of kernel or rootfs fails (default)
Var
1 – do not rollback
45
Software Description
Description
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CP6930 User Guide
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