diff --git a/app/src/controller.c b/app/src/controller.c
index 6bfb80d3..da90fbf1 100644
--- a/app/src/controller.c
+++ b/app/src/controller.c
@@ -60,12 +60,12 @@ static bool
 process_msg(struct controller *controller,
               const struct control_msg *msg) {
     static unsigned char serialized_msg[CONTROL_MSG_MAX_SIZE];
-    int length = control_msg_serialize(msg, serialized_msg);
+    size_t length = control_msg_serialize(msg, serialized_msg);
     if (!length) {
         return false;
     }
     int w = net_send_all(controller->control_socket, serialized_msg, length);
-    return w == length;
+    return (size_t) w == length;
 }
 
 static int
diff --git a/app/tests/test_control_msg_serialize.c b/app/tests/test_control_msg_serialize.c
index ffd5f300..dc6e0821 100644
--- a/app/tests/test_control_msg_serialize.c
+++ b/app/tests/test_control_msg_serialize.c
@@ -17,7 +17,7 @@ static void test_serialize_inject_keycode(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 14);
 
     const unsigned char expected[] = {
@@ -39,7 +39,7 @@ static void test_serialize_inject_text(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 18);
 
     const unsigned char expected[] = {
@@ -59,7 +59,7 @@ static void test_serialize_inject_text_long(void) {
     msg.inject_text.text = text;
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 5 + CONTROL_MSG_INJECT_TEXT_MAX_LENGTH);
 
     unsigned char expected[5 + CONTROL_MSG_INJECT_TEXT_MAX_LENGTH];
@@ -95,7 +95,7 @@ static void test_serialize_inject_touch_event(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 28);
 
     const unsigned char expected[] = {
@@ -130,7 +130,7 @@ static void test_serialize_inject_scroll_event(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 21);
 
     const unsigned char expected[] = {
@@ -149,7 +149,7 @@ static void test_serialize_back_or_screen_on(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 1);
 
     const unsigned char expected[] = {
@@ -164,7 +164,7 @@ static void test_serialize_expand_notification_panel(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 1);
 
     const unsigned char expected[] = {
@@ -179,7 +179,7 @@ static void test_serialize_collapse_notification_panel(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 1);
 
     const unsigned char expected[] = {
@@ -194,7 +194,7 @@ static void test_serialize_get_clipboard(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 1);
 
     const unsigned char expected[] = {
@@ -213,7 +213,7 @@ static void test_serialize_set_clipboard(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 19);
 
     const unsigned char expected[] = {
@@ -234,7 +234,7 @@ static void test_serialize_set_screen_power_mode(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 2);
 
     const unsigned char expected[] = {
@@ -250,7 +250,7 @@ static void test_serialize_rotate_device(void) {
     };
 
     unsigned char buf[CONTROL_MSG_MAX_SIZE];
-    int size = control_msg_serialize(&msg, buf);
+    size_t size = control_msg_serialize(&msg, buf);
     assert(size == 1);
 
     const unsigned char expected[] = {