3516无法通过USB烧写

RT，再使用USB烧写3516dv300的时提示接收命令返回超时。。。。。，如图所示，

根据提示已经降低了速率至1k,但是并没有什么卵用，打开debug调试后发现打印了一堆如下的消息:
If your boot is not the lastest one,
there may be non-answer from board during executing command.
Please be patient for waiting.
The time may be :        10s.
To send command frame, send timeout=10s, wait response timeout=30ms data is :
ab,00,22,6d,6d,63,20,77,72,69,74,65,20,30,78,30,20,30,78,38,31,30,30,30,30,30,30,20,30,78,30,20,30,78,32,31,35
Debug: Send data is :
ab,00,22,6d,6d,63,20,77,72,69,74,65,20,30,78,30,20,30,78,38,31,30,30,30,30,30,30,20,30,78,30,20,30,78,32,31,35
Usb driver error:-7
To send command frame, send timeout=10s, wait response timeout=30ms data is :
ab,00,0f,67,65,74,69,6e,66,6f,20,64,64,72,66,72,65,65
Debug: Send data is :
ab,00,0f,67,65,74,69,6e,66,6f,20,64,64,72,66,72,65,65
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7
Usb driver error:-7

PS：网口和串口可以正常烧写，且使用USB能够烧写到ddr，但是就是烧写不进去emmc，在2.0.1.0版本的sdk上均可以正常烧写，但是换到2.0.2.0就不行了，有大佬遇到过类似的问题吗，求指点迷津，感激不尽！