diff --git a/doc/README.kconfig b/doc/README.kconfig
index cd549a8a5441b932dd8275efddaf806473da930b..3aad5b4185b5c6bf66887c4d7d02d3bcebb3f41f 100644
--- a/doc/README.kconfig
+++ b/doc/README.kconfig
@@ -114,6 +114,13 @@ See below for how each configuration target works in U-Boot:
   coalesced together with "<condition:>" prefix for each line as shown above.
   This file can be used as an input of "defconfig" target.
 
+- <board>_config
+
+  This does not exist in Linux's Kconfig.
+  Prior to Kconfig, in U-Boot, "make <board>_config" was used for the
+  configuration.  It is still supported for backward compatibility and
+  its behavior is the same as "make <board>_defconfig".
+
 
 Migration steps to Kconfig
 --------------------------
diff --git a/scripts/multiconfig.sh b/scripts/multiconfig.sh
index 56cf0c2a5d56a19821f7a80038b3d03f0c27efcf..4190798a9762effc774cb7195de6eebc9bd1a274 100644
--- a/scripts/multiconfig.sh
+++ b/scripts/multiconfig.sh
@@ -248,6 +248,7 @@ case $target in
 *_defconfig)
 	do_board_defconfig $target;;
 *_config)
+	# backward compatibility
 	do_board_defconfig ${target%_config}_defconfig;;
 silentoldconfig)
 	do_silentoldconfig;;