U-boot environment: Difference between revisions
From embeddedTS Manuals
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The SPI flash contains both the U-Boot executable binary and U-Boot environment. Our default build has 8KB of environment space which can be used for variables and boot scripts. The following commands are relevant to manipulating the environment: | |||
<source lang=bash> | <source lang=bash> | ||
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</source> | </source> | ||
For a | For example, a to add a custom kernel cmdline option like "debug": | ||
<source lang=bash> | <source lang=bash> | ||
env set cmdline_append 'console=ttymxc0,115200 ro init=/sbin/init debug' | env set cmdline_append 'console=ttymxc0,115200 ro init=/sbin/init debug' | ||
env save | env save | ||
</source> | </source> | ||
Revision as of 15:36, 14 February 2017
The SPI flash contains both the U-Boot executable binary and U-Boot environment. Our default build has 8KB of environment space which can be used for variables and boot scripts. The following commands are relevant to manipulating the environment:
# Print all environment variables
env print -a
# Sets the variable bootdelay to 5 seconds
env set bootdelay 5;
# Variables can also contain commands
env set hellocmd 'led red on; echo Hello world; led green on;'
# Execute commands saved in a variable
env run hellocmd;
# Commit env changes to the spi flash
# Otherwise changes are lost
env save
# Restore env to default
env default -a
# Remove a variable
env delete emmcboot
For example, a to add a custom kernel cmdline option like "debug":
env set cmdline_append 'console=ttymxc0,115200 ro init=/sbin/init debug'
env save