diff --git a/src/gps.c b/src/gps.c
--- a/src/gps.c
+++ b/src/gps.c
@@ -63,6 +63,7 @@ void gps_update_position()
     uint8_t request[8] = {0xB5, 0x62, 0x01, 0x02, 0x00, 0x00, 0x03,
         0x0A};
     //_gps_send_msg(request, 8);
+    uint8_t flushed = uart_gethandle()->Instance->RDR;
     HAL_UART_Transmit(uart_gethandle(), request, 8, 100);
 
     uint8_t buf[36];
@@ -89,7 +90,8 @@ void gps_update_position()
     position.altitude = (int32_t)buf[22] | (int32_t)buf[23] << 8 |
         (int32_t)buf[24] << 16 | (int32_t)buf[25] << 24;
 
-    //if( !_gps_verify_checksum(&buf[2], 32) ) led_set(LED_RED, 1);
+    if( !_gps_verify_checksum(&buf[2], 32) )
+        led_blink(2);
 }
 
 
@@ -98,6 +100,7 @@ void gps_update_time(uint8_t* hour, uint
     // Send a NAV-TIMEUTC message to the receiver
     uint8_t request[8] = {0xB5, 0x62, 0x01, 0x21, 0x00, 0x00,
         0x22, 0x67};
+    uint8_t flushed = uart_gethandle()->Instance->RDR;
     HAL_UART_Transmit(uart_gethandle(), request, 8, 100);
 
     // Get the message back from the GPS
@@ -126,6 +129,7 @@ void gps_check_lock(uint8_t* lock, uint8
     // Construct the request to the GPS
     uint8_t request[8] = {0xB5, 0x62, 0x01, 0x06, 0x00, 0x00,
         0x07, 0x16};
+    uint8_t flushed = uart_gethandle()->Instance->RDR;
     HAL_UART_Transmit(uart_gethandle(), request, 8, 100);
 
     // Get the message back from the GPS
@@ -158,6 +162,7 @@ uint8_t gps_check_nav(void)
 {
     uint8_t request[8] = {0xB5, 0x62, 0x06, 0x24, 0x00, 0x00,
         0x2A, 0x84};
+    uint8_t flushed = uart_gethandle()->Instance->RDR;
     HAL_UART_Transmit(uart_gethandle(), request, 8, 100);
 
     // Get the message back from the GPS