diff --git a/epd-waveshare/src/epd3in7/mod.rs b/epd-waveshare/src/epd3in7/mod.rs
index 39adba2..e847214 100644
--- a/epd-waveshare/src/epd3in7/mod.rs
+++ b/epd-waveshare/src/epd3in7/mod.rs
@@ -218,6 +218,36 @@ where
         Ok(())
     }
 
+    /**
+    void EPD_3IN7_1Gray_Display_Part(const UBYTE *Image, UWORD Xstart, UWORD Ystart, UWORD Xend, UWORD Yend)
+    {
+      UWORD i, Width;
+      Width = (Xend-Xstart)%8 == 0 ? (Xend-Xstart)/8 : (Xend-Xstart)/8+1;
+      UWORD IMAGE_COUNTER = Width * (Yend-Ystart);
+
+      EPD_3IN7_SendCommand(0x44);
+      EPD_3IN7_SendData(Xstart & 0xff);
+      EPD_3IN7_SendData((Xstart>>8) & 0x03);
+      EPD_3IN7_SendData(Xend & 0xff);
+      EPD_3IN7_SendData((Xend>>8) & 0x03);
+      EPD_3IN7_SendCommand(0x45);
+      EPD_3IN7_SendData(Ystart & 0xff);
+      EPD_3IN7_SendData((Ystart>>8) & 0x03);
+      EPD_3IN7_SendData(Yend & 0xff);
+      EPD_3IN7_SendData((Yend>>8) & 0x03);
+
+      EPD_3IN7_SendCommand(0x24);
+      for (i = 0; i < IMAGE_COUNTER; i++)
+      {
+        EPD_3IN7_SendData(Image[i]);
+      }
+
+      EPD_3IN7_Load_LUT(2);
+      EPD_3IN7_SendCommand(0x20);
+      EPD_3IN7_ReadBusy_HIGH();
+    }
+     */
+
     #[allow(unused)]
     fn update_partial_frame(
         &mut self,
@@ -229,6 +259,20 @@ where
         width: u32,
         height: u32,
     ) -> Result<(), SPI::Error> {
+        self.interface
+            .cmd(spi, Command::SetRamXAddressStartEndPosition);
+
+        self.interface.data(spi, &[x as u8 & 0xff]);
+        self.interface.data(spi, &[(x >> 8) as u8 & 0x03]);
+        self.interface.data(spi, &[(width - x) as u8 & 0xff]);
+        self.interface.data(spi, &[((width - x) as u8 >> 8) & 0x03]);
+
+        self.interface
+            .cmd(spi, Command::SetRamYAddressStartEndPosition);
+        self.interface.data(spi, y as u8 & 0xff);
+        self.interface.data(spi, (y as u8 >> 8) & 0x03);
+        self.interface.data(spi, (height - y) as u8 & 0xff);
+        self.interface.data(spi, ((height - y) as u8 >> 8) & 0x03);
         todo!()
     }
 
@@ -236,7 +280,7 @@ where
         //self.interface
         //    .cmd_with_data(spi, Command::WRITE_LUT_REGISTER, &LUT_1GRAY_GC)?;
         self.interface.cmd(spi, Command::DisplayUpdateSequence)?;
-        self.interface.wait_until_idle(delay, IS_BUSY_LOW);
+        let _ = self.interface.wait_until_idle(delay, IS_BUSY_LOW);
         Ok(())
     }