diff --git a/meta/classes-recipe/uboot-config.bbclass b/meta/classes-recipe/uboot-config.bbclass
index bf21961977..74992182c3 100644
--- a/meta/classes-recipe/uboot-config.bbclass
+++ b/meta/classes-recipe/uboot-config.bbclass
@@ -144,7 +144,7 @@ python () {
             # Ensure the uboot specific menuconfig settings do not leak into other recipes
             if 'u-boot' in recipename:
                 if len(ubootconfig) == 1:
-                    d.setVar('KCONFIG_CONFIG_ROOTDIR', os.path.join(d.getVar("B"), d.getVar("UBOOT_MACHINE").strip()))
+                    d.setVar('KCONFIG_CONFIG_ROOTDIR', os.path.join("${B}", d.getVar("UBOOT_MACHINE").strip()))
                 else:
                     # Disable menuconfig for multiple configs
                     d.setVar('KCONFIG_CONFIG_ENABLE_MENUCONFIG', "false")