diff --git a/toolchain/toolchain-external/toolchain-external.mk b/toolchain/toolchain-external/toolchain-external.mk
index c73cc4ae4d..70781db0ff 100644
--- a/toolchain/toolchain-external/toolchain-external.mk
+++ b/toolchain/toolchain-external/toolchain-external.mk
@@ -466,11 +466,9 @@ define TOOLCHAIN_EXTERNAL_CONFIGURE_CMDS
 		@echo "External toolchain doesn't support --sysroot. Cannot use." ; \
 		exit 1 ; \
 	fi ; \
-	if [ "$(BR2_TOOLCHAIN_EXTERNAL_CUSTOM)" = "y" ]; then \
-		$(call check_kernel_headers_version,\
-			$(call toolchain_find_sysroot,$(TOOLCHAIN_EXTERNAL_CC) $(TOOLCHAIN_EXTERNAL_CFLAGS)),\
-			$(call qstrip,$(BR2_TOOLCHAIN_HEADERS_AT_LEAST))); \
-	fi ; \
+	$(call check_kernel_headers_version,\
+		$(call toolchain_find_sysroot,$(TOOLCHAIN_EXTERNAL_CC) $(TOOLCHAIN_EXTERNAL_CFLAGS)),\
+		$(call qstrip,$(BR2_TOOLCHAIN_HEADERS_AT_LEAST))); \
 	if test "$(BR2_arm)" = "y" ; then \
 		$(call check_arm_abi,\
 			"$(TOOLCHAIN_EXTERNAL_CC) $(TOOLCHAIN_EXTERNAL_CFLAGS)",\