fix

tools/laptop_device_build/Dockerfile

@@ -1,5 +1,7 @@
 FROM ghcr.io/commaai/openpilot-base-aarch64:latest
 
+ARG CAPNP_VERSION=1.3.0
+
 ENV PYTHONUNBUFFERED=1
 ENV UV_LINK_MODE=copy
 WORKDIR /work
@@ -7,6 +9,8 @@ WORKDIR /work
 # Keep this image minimal; dependency resolution is done by uv inside the workspace.
 # rsync/ssh-client are needed for optional sysroot sync from a comma device.
 RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates \
+    curl \
     rsync \
     openssh-client \
     e2fsprogs \
@@ -14,12 +18,26 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     qemu-user-static \
     gcc-aarch64-linux-gnu \
     g++-aarch64-linux-gnu \
+    cmake \
     qtbase5-private-dev \
     python3-pip \
     xz-utils \
     git \
   && rm -rf /var/lib/apt/lists/*
 
+RUN set -eux; \
+    tmpdir="$(mktemp -d)"; \
+    curl -fsSL "https://github.com/capnproto/capnproto/archive/refs/tags/v${CAPNP_VERSION}.tar.gz" | tar -xz -C "${tmpdir}"; \
+    cmake -S "${tmpdir}/capnproto-${CAPNP_VERSION}/c++" -B "${tmpdir}/build" \
+      -DBUILD_TESTING=OFF \
+      -DCMAKE_BUILD_TYPE=Release \
+      -DCMAKE_INSTALL_PREFIX=/usr/local; \
+    cmake --build "${tmpdir}/build" -j"$(nproc)"; \
+    cmake --install "${tmpdir}/build"; \
+    ldconfig; \
+    capnp --version; \
+    rm -rf "${tmpdir}"
+
 RUN /usr/bin/python3 -m pip install --no-cache-dir --break-system-packages uv
 
 # Fix for "dubious ownership" git errors when mounting folders on Linux hosts.