diff --git a/tools/Config.mk b/tools/Config.mk
index 2529fce19aa..c3eb0303b0a 100644
--- a/tools/Config.mk
+++ b/tools/Config.mk
@@ -138,7 +138,7 @@ endif
 # Process board-specific directories
 
 ifeq ($(CONFIG_ARCH_BOARD_CUSTOM),y)
-	CUSTOM_DIR = $(patsubst "%",%,$(CONFIG_ARCH_BOARD_CUSTOM_DIR))
+  CUSTOM_DIR = $(patsubst "%",%,$(CONFIG_ARCH_BOARD_CUSTOM_DIR))
 ifeq ($(CONFIG_ARCH_BOARD_CUSTOM_DIR_RELPATH),y)
   BOARD_DIR ?= $(TOPDIR)$(DELIM)$(CUSTOM_DIR)
 else