diff --git a/Dockerfile b/Dockerfile
index 4f32a0a..07bf362 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -10,11 +10,19 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     supervisor \
     && rm -rf /var/lib/apt/lists/*
 
-# Install bambu-lab-cloud-api without deps (opencv-python is declared but unused at runtime)
+# Install bambu-lab-cloud-api without deps (opencv-python is declared but unused at runtime).
+# Then stub out opencv-python so pip's resolver considers it satisfied and won't try to
+# build it from source (no C compiler, no armv7l wheel available).
 RUN pip install --no-cache-dir bambu-lab-cloud-api --no-deps && \
-    pip install --no-cache-dir paho-mqtt requests flask flask-cors flask-limiter
+    pip install --no-cache-dir paho-mqtt requests flask flask-cors flask-limiter && \
+    python3 -c "import site, pathlib; \
+        d = pathlib.Path(site.getsitepackages()[0]) / 'opencv_python-4.99.0.dist-info'; \
+        d.mkdir(); \
+        (d / 'METADATA').write_text('Metadata-Version: 2.1\nName: opencv-python\nVersion: 4.99.0\n'); \
+        (d / 'INSTALLER').write_text('pip\n'); \
+        (d / 'RECORD').write_text('')"
 
-# Install project and remaining dependencies
+# Install project and remaining dependencies (pip sees opencv-python already satisfied)
 COPY pyproject.toml .
 RUN pip install --no-cache-dir ".[standalone]"