apex-env - user-mode access to APEX flash environment
COMMAND [ ARGS ...
is a utility for viewing and modifying the environment used by
the APEX Boot Loader to define how the system will boot. APEX has a predefined
set of environment variables, determined by the build-time configuration, that
control operation of the boot loader.
Embedded in the APEX image is a linking structure that apex-env
identify the boot loader image and to locate information about the environment
variables as well as the flash region that holds the user-modified values. If
APEX is built without enabling this user-modifiable flash region,
will only allow the user to browse the variables and the
depends on the /dev/mtd
driver to locate the APEX. It
first looks for a partition named 'Loader', but it will also check the first
partition in case APEX is used as the primary boot loader.
The user may need root privileges to run apex-env
, even when only reading
- describe [KEY]
- Displays a description of KEY or descriptions of
every environment variable is KEY is omitted.
- Displays the contents of the flash environment region in a
hexadecimal/ASCII format useful for troubleshooting.
- Clears the environment region by setting all of the bytes
to 0xff. Use this command with care. Assuming that APEX was properly built
for your system, it still relies on the caching feature of the MTD block
driver to modify only a portion of a flash eraseblock. Be mindful that
interrupting this command after the block is erased and before the
important data has been restored could render the system unbootable.
- printenv [KEY]
- Displays the value of KEY or the values of every
environment variable if KEY is omitted. The separator between the
key and the value is =* for default values or just = when the default
value has been overridden by a value saved in the flash environment.
- setenv KEY VALUE
- Overrides the default value of KEY with
VALUE. Use quoting to prevent the shell from splitting VALUE
into separate words and from interpolation.
- unsetenv KEY
- Restores the default value of KEY by marking any
value stored in flash as deleted.
- apex-env printenv
- Show all of the environment variables and the current
values for each.
- apex-env setenv startup 'copy $kernelsrc $bootaddr ;
- Change the startup variable to copy the kernel and
- apex-env dump | head
- Examine the first few bytes of the environment data.
Marc Singer <email@example.com>