diff --git a/.clusterfuzzlite/Dockerfile b/.clusterfuzzlite/Dockerfile
index 2fe909a9b..8b7136005 100644
--- a/.clusterfuzzlite/Dockerfile
+++ b/.clusterfuzzlite/Dockerfile
@@ -43,5 +43,11 @@ COPY ./.clusterfuzzlite/build.sh $SRC/
 WORKDIR $SRC/firmware
 COPY . $SRC/firmware/
 
-ENV PIO_ENV=buildroot
+# https://docs.platformio.org/en/latest/envvars.html
+ENV PLATFORMIO_WORKSPACE_DIR=$WORK/pio \
+    PLATFORMIO_CORE_DIR=$SRC/pio/core \
+    PLATFORMIO_LIBDEPS_DIR=$SRC/pio/libdeps \
+    PLATFORMIO_PACKAGES_DIR=$SRC/pio/packages \
+    PLATFORMIO_SETTING_ENABLE_CACHE=No \
+    PIO_ENV=buildroot
 RUN platformio pkg install --environment $PIO_ENV
diff --git a/.clusterfuzzlite/build.sh b/.clusterfuzzlite/build.sh
index 0f2428e76..781ad9ea6 100644
--- a/.clusterfuzzlite/build.sh
+++ b/.clusterfuzzlite/build.sh
@@ -8,25 +8,25 @@ env
 cd "$SRC"
 NPROC=$(nproc || echo 1)
 
-LDFLAGS=-lpthread cmake -S "$SRC/yaml-cpp" -B "$SRC/yaml-cpp/build" \
+LDFLAGS=-lpthread cmake -S "$SRC/yaml-cpp" -B "$WORK/yaml-cpp" \
 	-DBUILD_SHARED_LIBS=OFF
-cmake --build "$SRC/yaml-cpp/build" -j "$NPROC"
-cmake --install "$SRC/yaml-cpp/build" --prefix /usr
+cmake --build "$WORK/yaml-cpp" -j "$NPROC"
+cmake --install "$WORK/yaml-cpp" --prefix /usr
 
-cmake -S "$SRC/orcania" -B "$SRC/orcania/build" \
+cmake -S "$SRC/orcania" -B "$WORK/orcania" \
 	-DBUILD_STATIC=ON
-cmake --build "$SRC/orcania/build" -j "$NPROC"
-cmake --install "$SRC/orcania/build" --prefix /usr
+cmake --build "$WORK/orcania" -j "$NPROC"
+cmake --install "$WORK/orcania" --prefix /usr
 
-cmake -S "$SRC/yder" -B "$SRC/yder/build" \
+cmake -S "$SRC/yder" -B "$WORK/yder" \
 	-DBUILD_STATIC=ON -DWITH_JOURNALD=OFF
-cmake --build "$SRC/yder/build" -j "$NPROC"
-cmake --install "$SRC/yder/build" --prefix /usr
+cmake --build "$WORK/yder" -j "$NPROC"
+cmake --install "$WORK/yder" --prefix /usr
 
-cmake -S "$SRC/ulfius" -B "$SRC/ulfius/build" \
+cmake -S "$SRC/ulfius" -B "$WORK/ulfius" \
 	-DBUILD_STATIC=ON -DWITH_JANSSON=OFF -DWITH_CURL=OFF -DWITH_WEBSOCKET=OFF
-cmake --build "$SRC/ulfius/build" -j "$NPROC"
-cmake --install "$SRC/ulfius/build" --prefix /usr
+cmake --build "$WORK/ulfius" -j "$NPROC"
+cmake --install "$WORK/ulfius" --prefix /usr
 
 cd "$SRC/firmware"
 
@@ -50,10 +50,11 @@ for f in .clusterfuzzlite/*_fuzzer.cpp; do
 	fuzzer=$(basename "$f" .cpp)
 	cp -f "$f" src/fuzzer.cpp
 	pio run -vvv --environment "$PIO_ENV"
-	cp ".pio/build/$PIO_ENV/program" "$OUT/$fuzzer"
+	program="$PLATFORMIO_WORKSPACE_DIR/build/$PIO_ENV/program"
+	cp "$program" "$OUT/$fuzzer"
 
 	# Copy shared libraries used by the fuzzer.
-	read -ra shared_libs < <(ldd ".pio/build/$PIO_ENV/program" | sed -n 's/[^=]\+=> \([^ ]\+\).*/\1/p')
+	read -ra shared_libs < <(ldd "$program" | sed -n 's/[^=]\+=> \([^ ]\+\).*/\1/p')
 	cp -f "${shared_libs[@]}" "$OUT/lib/"
 
 	# Build the initial fuzzer seed corpus.
diff --git a/platformio.ini b/platformio.ini
index 6a4466c01..259b2ec8c 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -20,7 +20,7 @@ extra_scripts = bin/platformio-custom.py
 build_flags = -Wno-missing-field-initializers
 
 	-Wno-format
-	-Isrc -Isrc/mesh -Isrc/mesh/generated -Isrc/gps -Isrc/buzz -Wl,-Map,.pio/build/output.map
+	-Isrc -Isrc/mesh -Isrc/mesh/generated -Isrc/gps -Isrc/buzz -Wl,-Map,${platformio.build_dir}/output.map
 	-DUSE_THREAD_NAMES
 	-DTINYGPS_OPTION_NO_CUSTOM_FIELDS
 	-DPB_ENABLE_MALLOC=1