diff --git a/02_Arduino/hoverserial/hoverserial.ino b/02_Arduino/hoverserial/hoverserial.ino
index ba63ad9..d6908c3 100644
--- a/02_Arduino/hoverserial/hoverserial.ino
+++ b/02_Arduino/hoverserial/hoverserial.ino
@@ -91,8 +91,8 @@ void Receive()
 {
 	// Check for new data availability in the Serial buffer
 	if (HoverSerial.available()) {
-		incomingByte 	  = HoverSerial.read();		                                // Read the incoming byte
-		bufStartFrame	= ((uint16_t)(incomingBytePrev) << 8) +  incomingByte;	// Construct the start marker		
+		incomingByte 	  = HoverSerial.read();		                              // Read the incoming byte
+		bufStartFrame	= ((uint16_t)(incomingBytePrev) << 8) +  incomingByte;	// Construct the start frame		
 	}
 	else {
 		return;
@@ -118,8 +118,8 @@ void Receive()
 	// Check if we reached the end of the package
 	if (idx == sizeof(SerialFeedback)) {  	
 		uint16_t checksum;
-		checksum = NewFeedback.start ^ NewFeedback.cmd1 ^ NewFeedback.cmd2 ^ NewFeedback.speedR ^ NewFeedback.speedL
-					^ NewFeedback.speedR_meas ^ NewFeedback.speedL_meas ^ NewFeedback.batVoltage ^ NewFeedback.boardTemp;
+		checksum = (uint16_t)(NewFeedback.start ^ NewFeedback.cmd1 ^ NewFeedback.cmd2 ^ NewFeedback.speedR ^ NewFeedback.speedL
+					^ NewFeedback.speedR_meas ^ NewFeedback.speedL_meas ^ NewFeedback.batVoltage ^ NewFeedback.boardTemp);
 	
 		// Check validity of the new data
 		if (NewFeedback.start == START_FRAME && checksum == NewFeedback.checksum) {
diff --git a/README.md b/README.md
index 70f0dd4..519c8e2 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,8 @@
 # hoverboard-firmware-hack-FOC
 ## with Field Oriented Control (FOC)
 [![Build Status](https://travis-ci.com/EmanuelFeru/hoverboard-firmware-hack-FOC.svg?branch=master)](https://travis-ci.com/EmanuelFeru/hoverboard-firmware-hack-FOC)
+[![paypal](https://www.paypalobjects.com/en_US/i/btn/btn_donateCC_LG.gif)](https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=feru_emanuel%40yahoo.com&currency_code=EUR&source=url)
+***If you like this project, you can give me a cup of coffee. Thanks!*** 
 
 This repository implements Field Oriented Control (FOC) for stock hoverboards. Compared to the commutation method, this new FOC control method offers superior performance featuring:
  - reduced noise and vibrations 	
diff --git a/Src/main.c b/Src/main.c
index 3f3b601..983888c 100644
--- a/Src/main.c
+++ b/Src/main.c
@@ -330,8 +330,7 @@ int main(void) {
     #if defined CONTROL_SERIAL_USART2 || defined CONTROL_SERIAL_USART3
 
       // Handle received data validity, timeout and fix out-of-sync if necessary
-      //if (command.start == START_FRAME && command.checksum == (command.start ^ command.steer ^ command.speed)) {
-      if (command.start == START_FRAME && command.checksum == (command.start ^ command.speedLeft ^ command.speedRight)) {
+      if (command.start == START_FRAME && command.checksum == (uint16_t)(command.start ^ command.speedLeft ^ command.speedRight)) {
         if (timeoutFlag) {                      // Check for previous timeout flag
           if (timeoutCnt-- <= 0)                // Timeout de-qualification
             timeoutFlag   = 0;                  // Timeout flag cleared
@@ -353,7 +352,7 @@ int main(void) {
           enable = 1;                       // enable motors
           consoleLog("-- Motors enabled --\r\n");
         }
-        
+
       } else {
         if (timeoutCnt++ >= SERIAL_TIMEOUT) {   // Timeout qualification
           timeoutFlag     = 1;                  // Timeout detected