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CP3923 User Guide
49
There are three different types of bootloader environment variables:
•
Script: The variable is a set of consecutive (more simple) bootloader commands to perform a specific task. A com-
mand script is invoked using the ‘run <script>’ syntax. E.g. the ‘run clear_env’ command would erase the boot-
loader environment sectors causing the bootloader to use its default environment upon next restart.
•
Var: The variable controls a specific behaviour of the bootloader startup sequence. E.g. the ‘bootdelay’ variable
controls the time u-boot waits before execution of the bootcmd which normally loads and starts the linux kernel.
•
Auto: The variable is automatically set during bootloader startup sequence. E.g. the ‘postresult’ variable stores
the result of the POST.
It is possible to modify envionment variables and start the pre-defined scripts form the bootloader shell. It is strongly dis-
couraged to modify the pre-defined script variables. However, definition and execution of user-defined script variables can
be done.
postresult
Auto
Stores the POST result
0 – no POST error occurred
1 – a POST error occurred
recover_flash
Script
Command script that is executed when the onboard flash is corrupted
reset_unknown
Var
0 – do not cold reset when unknown reset type is detected
1 – enable cold reset when unknown reset type is detected (default)
ignore_posterr
Var
0 – ignore POST errors (default)
1 – Start CLI on POST errors
uboot_flash_update
Script
Command script to flash a U-Boot binary image transferred with tftp-
boot to the active image bootloader
watchdogboot
Var
0 – disable boot monitor watchdog
5...n – timeout in seconds before boot monitor watchdog fires
default: 45
Note: This is the pBMWD watchdog.
watchdogos
Var
0 – disable OS load watchdog
15..dis.n – timeout in seconds before load OS watchdog fires
default: 45
Note: This is the pOSWD watchdog.
Note...
Meddling with the bootloader environment variables can affect significantly the
startup sequence of the board and may cause the system to be un-bootable.
Table 4-3:
Bootloader Shell Options (Continued)
Name
Type
Description
