diff --git a/etc/makefiles/sketch.mk b/etc/makefiles/sketch.mk
index 4a3743ad..e3cd2151 100644
--- a/etc/makefiles/sketch.mk
+++ b/etc/makefiles/sketch.mk
@@ -165,7 +165,7 @@ compile: kaleidoscope-hardware-configured
 
 	$(QUIET) install -d "${OUTPUT_PATH}"
 	$(QUIET) $(ARDUINO_CLI) compile --fqbn "${FQBN}" ${ARDUINO_VERBOSE} --warnings all ${ccache_wrapper_property} ${local_cflags_property} \
-	  ${_arduino_local_libraries_prop} \
+	  ${_arduino_local_libraries_prop} ${_ARDUINO_CLI_COMPILE_CUSTOM_FLAGS} \
 	  --library "${KALEIDOSCOPE_DIR}" \
 	  --libraries "${KALEIDOSCOPE_DIR}/plugins/" \
 	  --build-path "${BUILD_PATH}" \
diff --git a/testing/makefiles/testcase.mk b/testing/makefiles/testcase.mk
index 15ed42c3..60cacbd4 100644
--- a/testing/makefiles/testcase.mk
+++ b/testing/makefiles/testcase.mk
@@ -78,6 +78,7 @@ compile-sketch: ${TEST_OBJS}
 	@install -d "${BIN_DIR}" "${LIB_DIR}"
 	$(QUIET) env LIBONLY=yes VERBOSE=${VERBOSE}  \
 		OUTPUT_PATH="${LIB_DIR}" \
+		_ARDUINO_CLI_COMPILE_CUSTOM_FLAGS='--build-property upload.maximum_size=""' \
 		$(MAKE) -f ${top_dir}/etc/makefiles/sketch.mk compile
 	$(QUIET) $(COMPILER_WRAPPER) $(call _arduino_prop,compiler.cpp.cmd) -o "${BIN_DIR}/${BIN_FILE}" \
 		-lpthread -g -w ${TEST_OBJS} \