diff --git a/c/lib/e-Paper/EPD_7in5_V2.c b/c/lib/e-Paper/EPD_7in5_V2.c
index a2584c5..55a8331 100644
--- a/c/lib/e-Paper/EPD_7in5_V2.c
+++ b/c/lib/e-Paper/EPD_7in5_V2.c
@@ -349,13 +349,13 @@ void EPD_7IN5_V2_Display_Part(UBYTE *blackimage,UDOUBLE x_start, UDOUBLE y_start
 	EPD_SendData (x_start%256);   //x-start    
 
 	EPD_SendData (x_end/256);		
-	EPD_SendData (x_end%256-1);  //x-end	
+	EPD_SendData ((x_end-1)%256);  //x-end	
 
 	EPD_SendData (y_start/256);  //
 	EPD_SendData (y_start%256);   //y-start    
 
 	EPD_SendData (y_end/256);		
-	EPD_SendData (y_end%256-1);  //y-end
+	EPD_SendData ((y_end-1)%256);  //y-end
 	EPD_SendData (0x01);
     
     EPD_SendCommand(0x13);
diff --git a/c/lib/e-Paper/EPD_7in5b_V2.c b/c/lib/e-Paper/EPD_7in5b_V2.c
index e3992e5..46f4b06 100644
--- a/c/lib/e-Paper/EPD_7in5b_V2.c
+++ b/c/lib/e-Paper/EPD_7in5b_V2.c
@@ -323,13 +323,13 @@ void EPD_7IN5B_V2_Display_Partial(const UBYTE *Image, UWORD Xstart, UWORD Ystart
 	EPD_7IN5B_V2_SendData(Xstart%256);   //x-start    
 
 	EPD_7IN5B_V2_SendData(Xend/256);		
-	EPD_7IN5B_V2_SendData(Xend%256-1);  //x-end	
+	EPD_7IN5B_V2_SendData((Xend-1)%256);  //x-end	
 
 	EPD_7IN5B_V2_SendData(Ystart/256);  //
 	EPD_7IN5B_V2_SendData(Ystart%256);   //y-start    
 
 	EPD_7IN5B_V2_SendData(Yend/256);		
-	EPD_7IN5B_V2_SendData(Yend%256-1);  //y-end
+	EPD_7IN5B_V2_SendData((Yend-1)%256);  //y-end
 	EPD_7IN5B_V2_SendData(0x01);		
 
     EPD_7IN5B_V2_SendCommand(0x10);   //Write Black and White image to RAM