dp83640调试出现问题，我使用的是HI3531和DP83640

1，目标板能ping通PC。

2，通过tftp下载内核时，下载一段时间后停止，不能继续下载。

send ack packet, int line 268 in tftp.c, block is 17
sending UDP to 0b01a8c0/b8:88:e3:37:f9:bb
send packet in stammc 46
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
get tftp packet type data
send ack packet, int line 268 in tftp.c, block is 18
sending UDP to 0b01a8c0/b8:88:e3:37:f9:bb
send packet in stammc 46
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
get tftp packet type data
send ack packet, int line 268 in tftp.c, block is 19
sending UDP to 0b01a8c0/b8:88:e3:37:f9:bb
send packet in stammc 46
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
get tftp packet type data
send ack packet, int line 268 in tftp.c, block is 20
sending UDP to 0b01a8c0/b8:88:e3:37:f9:bb
send packet in stammc 46
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
get tftp packet type data
send ack packet, int line 268 in tftp.c, block is 21
sending UDP to 0b01a8c0/b8:88:e3:37:f9:bb
send packet in stammc 46
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=60, v=45
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
get tftp packet type data
Same block again; ignore it. block is 21
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
packet received
packet received
Receive from protocol 0x800
recive ip packet
Got IP
len=1500, v=45
get tftp packet type data

可以看出，在板子收到第21个包后给回复信号。但是PC机没法收到。导致整个板子没法下载。现在没法定位问题想知道这种情况我该用怎样的调试思路。是硬件的问题还是软件的问题？

晕，刚刚发出来！这个问题我就自己解决了！原来是海思移植的hi3531的u-boot有问题。我通过修改ACK的次数，多次重传就能下载进去了！然后进入到内核里面，发现网卡是没得问题的！呵呵！开心！