diff --git a/.gitea/workflows/demo.yaml b/.gitea/workflows/demo.yaml
index 72d33ee85..e78d7a388 100644
--- a/.gitea/workflows/demo.yaml
+++ b/.gitea/workflows/demo.yaml
@@ -26,16 +26,17 @@ jobs:
       - name: Update initial docker image with apt-get
         run: |
           apt-get -qq update && DEBIAN_FRONTEND=noninteractive apt-get -qq install -y wget software-properties-common && \
-          wget https://developer.download.nvidia.com/compute/cuda/repos/${OS}/x86_64/cuda-${OS}.pin && \
-          mv cuda-${OS}.pin /etc/apt/preferences.d/cuda-repository-pin-600 && \
-          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/${OS}/x86_64/7fa2af80.pub && \
-          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/${OS}/x86_64/3bf863cc.pub && \
-          add-apt-repository "deb https://developer.download.nvidia.com/compute/cuda/repos/${OS}/x86_64/ /" && \
+
+          wget https://developer.download.nvidia.com/compute/cuda/repos/${OS}/x86_64/cuda-$OS.pin && \
+          mv cuda-$OS.pin /etc/apt/preferences.d/cuda-repository-pin-600 && \
+          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/$OS/x86_64/7fa2af80.pub && \
+          apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/$OS/x86_64/3bf863cc.pub && \
+          add-apt-repository "deb https://developer.download.nvidia.com/compute/cuda/repos/$OS/x86_64/ /" && \
 
           apt-get -qq update && apt-get -qq upgrade -y &&  \
-              DEBIAN_FRONTEND=noninteractive apt-get -qq install -y openjdk-11-jdk \
+              DEBIAN_FRONTEND=noninteractive apt-get -qq install -y \
               build-essential checkinstall zlib1g-dev libssl-dev git libpthread-stubs0-dev \
-              libcudnn8=${cudnn_version}-1+${cuda_version} libcudnn8-dev=${cudnn_version}-1+${cuda_version} \
+              libcudnn8=$cudnn_version-1+$cuda_version libcudnn8-dev=$cudnn_version-1+$cuda_version \
               cuda-drivers
 
       - name: Setup Java