diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index 49c6fb4..afcdc8c 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -903,7 +903,7 @@
     update-alternatives --install /usr/bin/cpp cpp /usr/bin/cpp-14 14
 
 # Set up LLVM apt repository.
-RUN bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" 19
+RUN bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" -- 19
 
 # Install extra clang tools
 RUN apt-get install -y \