diff --git a/client/comms.c b/client/comms.c
index 8e9eb0a64..038e90fea 100644
--- a/client/comms.c
+++ b/client/comms.c
@@ -319,7 +319,7 @@ __attribute__((force_align_arg_pointer))
 #endif
 *uart_communication(void *targ) {
     communication_arg_t *connection = (communication_arg_t *)targ;
-    size_t rxlen;
+    uint32_t rxlen;
 
     PacketResponseNG rx;
     PacketResponseNGRaw rx_raw;
diff --git a/uart/uart.h b/uart/uart.h
index 49900be39..4cbea26c8 100644
--- a/uart/uart.h
+++ b/uart/uart.h
@@ -88,13 +88,13 @@ void uart_close(const serial_port sp);
  * partial read may have completed into the buffer by the corresponding
  * implementation, so pszRxLen should be checked to see if any data was written.
  */
-bool uart_receive(const serial_port sp, uint8_t *pbtRx, size_t pszMaxRxLen, size_t *pszRxLen);
+bool uart_receive(const serial_port sp, uint8_t *pbtRx, uint32_t pszMaxRxLen, uint32_t *pszRxLen);
 
 /* Sends a buffer to a given serial port.
  *   pbtTx: A pointer to a buffer containing the data to send.
  *   len: The amount of data to be sent.
  */
-bool uart_send(const serial_port sp, const uint8_t *pbtTx, const size_t len);
+bool uart_send(const serial_port sp, const uint8_t *pbtTx, const uint32_t len);
 
 /* Sets the current speed of the serial port, in baud.
  */
diff --git a/uart/uart_posix.c b/uart/uart_posix.c
index e3b7c56b8..177088d05 100644
--- a/uart/uart_posix.c
+++ b/uart/uart_posix.c
@@ -234,8 +234,8 @@ void uart_close(const serial_port sp) {
     free(sp);
 }
 
-bool uart_receive(const serial_port sp, uint8_t *pbtRx, size_t pszMaxRxLen, size_t *pszRxLen) {
-    size_t byteCount;
+bool uart_receive(const serial_port sp, uint8_t *pbtRx, uint32_t pszMaxRxLen, uint32_t *pszRxLen) {
+    uint32_t byteCount;  // FIONREAD returns size on 32b
     fd_set rfds;
     struct timeval tv;
 
@@ -267,10 +267,12 @@ bool uart_receive(const serial_port sp, uint8_t *pbtRx, size_t pszMaxRxLen, size
 
         // Retrieve the count of the incoming bytes
         res = ioctl(((serial_port_unix *)sp)->fd, FIONREAD, &byteCount);
+        printf("UART:: RX ioctl res %d byteCount %u\n", res, byteCount);
         if (res < 0) return false;
 
         // Cap the number of bytes, so we don't overrun the buffer
         if (pszMaxRxLen - (*pszRxLen) < byteCount) {
+            printf("UART:: RX buffer overrun (have %u, need %u)\n", pszMaxRxLen - (*pszRxLen), byteCount);
             byteCount = pszMaxRxLen - (*pszRxLen);
         }
 
@@ -292,8 +294,8 @@ bool uart_receive(const serial_port sp, uint8_t *pbtRx, size_t pszMaxRxLen, size
     return true;
 }
 
-bool uart_send(const serial_port sp, const uint8_t *pbtTx, const size_t len) {
-    size_t pos = 0;
+bool uart_send(const serial_port sp, const uint8_t *pbtTx, const uint32_t len) {
+    uint32_t pos = 0;
     fd_set rfds;
     struct timeval tv;
 
diff --git a/uart/uart_win32.c b/uart/uart_win32.c
index c6e3142cf..36a10731a 100644
--- a/uart/uart_win32.c
+++ b/uart/uart_win32.c
@@ -169,11 +169,11 @@ uint32_t uart_get_speed(const serial_port sp) {
     return 0;
 }
 
-bool uart_receive(const serial_port sp, uint8_t *p_rx, size_t pszMaxRxLen, size_t *len) {
-    return ReadFile(((serial_port_windows *)sp)->hPort, p_rx, pszMaxRxLen, (LPDWORD)len, NULL);
+bool uart_receive(const serial_port sp, uint8_t *pbtRx, uint32_t pszMaxRxLen, uint32_t *pszRxLen) {
+    return ReadFile(((serial_port_windows *)sp)->hPort, pbtRx, pszMaxRxLen, (LPDWORD)pszRxLen, NULL);
 }
 
-bool uart_send(const serial_port sp, const uint8_t *p_tx, const size_t len) {
+bool uart_send(const serial_port sp, const uint8_t *p_tx, const uint32_t len) {
     DWORD txlen = 0;
     return WriteFile(((serial_port_windows *)sp)->hPort, p_tx, len, &txlen, NULL);
 }