diff --git a/meta/conf/distro/include/tcmode-default.inc b/meta/conf/distro/include/tcmode-default.inc
index 3720a4c5b8..0de858d3af 100644
--- a/meta/conf/distro/include/tcmode-default.inc
+++ b/meta/conf/distro/include/tcmode-default.inc
@@ -77,9 +77,9 @@ PREFERRED_VERSION_go-runtime ?= "${GOVERSION}"
 PREFERRED_VERSION_nativesdk-go ?= "${GOVERSION}"
 PREFERRED_VERSION_nativesdk-go-runtime ?= "${GOVERSION}"
 
-PREFERRED_VERSION_llvm = "${LLVMVERSION}"
-PREFERRED_VERSION_llvm-native = "${LLVMVERSION}"
-PREFERRED_VERSION_nativesdk-llvm = "${LLVMVERSION}"
+PREFERRED_VERSION_llvm ?= "${LLVMVERSION}"
+PREFERRED_VERSION_llvm-native ?= "${LLVMVERSION}"
+PREFERRED_VERSION_nativesdk-llvm ?= "${LLVMVERSION}"
 
 # Rust toolchain preferred versions: