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CP6930-1 User Guide
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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
Type
Description
bootargs
Var
Default kernel arguments. (mem=504M root=/dev/ram0 quiet)
bootcmd
Script
This variable defines a command string that is automatically executed
when the initial countdown is not interrupted.
This command is only executed when the variable bootdelay is also
defined!
bootcmdflash
Script
contains the standard startup script for loading OS image from flash
partition command. This will load the Linux kernel and start it with a
CRAMFS (TBC, maybe INITRD) type root file system.
bootcmdnet
Script
contains the standard startup script for loading OS image from net-
work
bootcmdprd
Script
contains the standard startup script for use during board production
bootcmdrecover
Script
contains standard startup script for board firmware recovery in boot
firmware
bootdelay
Var
After 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
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.
bootsource
Var
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
script, which may be overridden by the user.
default: flash
bootstopkey
Var
Defines the key phrase that the user needs to type to drop into the
bootloader command line interface during startup.
not set – use string “stop” as bootstop key phrase (default)
<any> - use string <any> as bootstop key phrase
clear_config
Script
Erase config partition to restore factory defaults for Linux BSP set-
tings.
clear_env
Script
Command script (use with “run clear_env”) that erases the U-Boot
environment for the active image
disable_rollback
Var
0 – rollback when CRC check of kernel or rootfs fails (default)
1 – do not rollback
ethact
Var
Default network interface used by network commands (bootp, tftp-
boot et al)
default: ppc_4xx_eth0
ethaddr
Auto
contains the default base MAC address of the board. If this is not set,
the MAC address from VPD is used.
flash_update
Script
Command script to flash a Linux kernel and rootfs image transferred
with tftpboot to the active Linux kernel and rootfs partition
loadaddr
Var
Default load address for network transfers. This is used as a temporary
storage for netbooting and firmware updates.
default: 0x20000000
memtest
Var
Controls POST memory test execution:
0: only data and address line test is executed
1: fast memory test with checkerboard pattern (tests 4MB of memory
divided on different 128kB memory chunks)
2: full memory test with checkerboard pattern
If not set, the fast memory test is performed
