diff --git a/net/apps/tftp.c b/net/apps/tftp.c
index 6094382d22afcf01e40b4457790610440f43951e..7e5b1f90d9938497e2eb0b4a6d65aaf7ab930c64 100644
--- a/net/apps/tftp.c
+++ b/net/apps/tftp.c
@@ -166,9 +166,13 @@ void tftp_put(const char* host, const char* dir, const char* filename)
 			tftp_buffer[3] = block_number & 0xff;
 
 			lwip_sendto(sock_fd, tftp_buffer, length + 4, 0, 
-				(struct sockaddr *)&tftp_addr, fromlen);
+				(struct sockaddr *)&from_addr, fromlen);
+		}
+		else
+		{
+			rt_kprintf("done\n");
+			break; /* no data yet */
 		}
-		else break; /* no data yet */
 
 		/* receive ack */
 		length = lwip_recvfrom(sock_fd, tftp_buffer, sizeof(tftp_buffer), 0, 
@@ -177,10 +181,11 @@ void tftp_put(const char* host, const char* dir, const char* filename)
 		{
 			if ((tftp_buffer[0] == 0 &&
 				tftp_buffer[1] == TFTP_ACK &&
-				tftp_buffer[3] == (block_number >> 8) & 0xff) &&
-				tftp_buffer[2] == (block_number & 0xff))
+				tftp_buffer[2] == (block_number >> 8) & 0xff) &&
+				tftp_buffer[3] == (block_number & 0xff))
 			{
 				block_number ++;
+				rt_kprintf("#");
 			}
 			else 
 			{
@@ -188,6 +193,11 @@ void tftp_put(const char* host, const char* dir, const char* filename)
 				break;
 			}
 		}
+		else if (length == 0)
+		{
+			rt_kprintf("server timeout\n");
+			break;
+		}
 	}
 
 	close(fd);