diff --git a/conf/distro/include/tcmode-external.inc b/conf/distro/include/tcmode-external.inc
index 189ba4f..7f5da81 100644
--- a/conf/distro/include/tcmode-external.inc
+++ b/conf/distro/include/tcmode-external.inc
@@ -1,5 +1,5 @@
 # Configuration to use external Sourcery G++ toolchain
-EXTERNAL_TOOLCHAIN ?= "UNDEFINED"
+EXTERNAL_TOOLCHAIN ??= "UNKNOWN"
 EXTERNAL_TARGET_SYS ??= "${TARGET_ARCH}-${TARGET_OS}"
 EXTERNAL_TOOLCHAIN_BIN ??= "${EXTERNAL_TOOLCHAIN}/bin"