diff --git a/tools/Config.mk b/tools/Config.mk
index 088be647c3d..2b43c26eb22 100644
--- a/tools/Config.mk
+++ b/tools/Config.mk
@@ -139,9 +139,9 @@ endif
 
 ifeq ($(CONFIG_ARCH_BOARD_CUSTOM),y)
 ifeq ($(CONFIG_ARCH_BOARD_CUSTOM_DIR_RELPATH),y)
-  BOARD_DIR ?= $(TOPDIR)$(DELIM)$(CONFIG_ARCH_BOARD_CUSTOM_DIR)$(DELIM)$(CONFIG_ARCH_BOARD)
+  BOARD_DIR ?= $(TOPDIR)$(DELIM)$(CONFIG_ARCH_BOARD_CUSTOM_DIR)
 else
-  BOARD_DIR ?= $(CONFIG_ARCH_BOARD_CUSTOM_DIR)$(DELIM)$(CONFIG_ARCH_BOARD)
+  BOARD_DIR ?= $(CONFIG_ARCH_BOARD_CUSTOM_DIR)
 endif
 else
   BOARD_DIR ?= $(TOPDIR)$(DELIM)boards$(DELIM)$(CONFIG_ARCH)$(DELIM)$(CONFIG_ARCH_CHIP)$(DELIM)$(CONFIG_ARCH_BOARD)