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+// -*- mode:doc; -*-
+// vim: set syntax=asciidoc:
+
+[[customize-store-basics]]
+=== Basics for storing the configuration
+
+When you have a buildroot configuration that you are satisfied with and
+you want to share it with others, put it under revision control or move
+on to a different buildroot project, you need to store the configuration
+so it can be rebuilt later. The configuration that needs to be stored
+consists of the buildroot configuration, the configuration files for
+packages that you use (kernel, busybox, uClibc, ...), and your rootfs
+modifications.
+
+[[customize-store-buildroot-config]]
+==== Buildroot configuration
+
+For storing the buildroot configuration itself, buildroot offers the
+following command: +make savedefconfig+.
+
+This strips the buildroot configuration down by removing configuration
+options that are at their default value. The result is stored in a file
+called +defconfig+.  If you want to save it in another place, change
+the +BR2_DEFCONFIG+ option, or call make with +make savedefconfig
+BR2_DEFCONFIG=<path-to-defconfig>+.  The usual place is
++configs/<boardname>_defconfig+. The configuration can then be rebuilt by
+running +make <boardname>_defconfig+.
+
+Alternatively, you can copy the file to any other place and rebuild with
++make defconfig BR2_DEFCONFIG=<path-to-defconfig-file>+.
+
+
+[[customize-store-package-config]]
+==== Other package configuration
+
+The configuration files for busybox, the linux kernel, barebox and
+uClibc should be stored as well if changed. For each of these, a
+buildroot configuration option exists to point to an input
+configuration file, e.g. +BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE+.  To
+save their configuration, set those configuration options to a path
+outside your output directory,
+e.g. +board/<manufacturer>/<boardname>/linux.config+.  Then, copy the
+configuration files to that path.
+
+Make sure that you create a configuration file 'before' changing
+the +BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE+ etc. options.  Otherwise,
+buildroot will try to access this config file, which doesn't exist
+yet, and will fail. You can create the configuration file by running
++make linux-menuconfig+ etc.
+
+Buildroot provides a few helper targets to make the saving of
+configuration files easier.
+
+* +make linux-update-defconfig+ saves the linux configuration to the
+  path specified by +BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE+.  It
+  simplifies the config file by removing default values.  However,
+  this only works with kernels starting from 2.6.33.  For earlier
+  kernels, use +make linux-update-config+.
+* +make busybox-update-config+ saves the busybox configuration to the
+  path specified by +BR2_PACKAGE_BUSYBOX_CONFIG+.
+* +make uclibc-update-config+ saves the uClibc configuration to the
+  path specified by +BR2_UCLIBC_CONFIG+.
+* +make barebox-update-defconfig+ saves the barebox configuration to the
+  path specified by +BR2_TARGET_BAREBOX_CUSTOM_CONFIG_FILE+.
+* For at91bootstrap3, no helper exists so you have to copy the config
+  file manually to +BR2_TARGET_AT91BOOTSTRAP3_CUSTOM_CONFIG_FILE+.
+
+