QFLASH Problem

I use common MSM8960 unbrick tool to flash my phone which connect to computer display QHSUSB_DLOAD, and driver install complete, but i flash the data, it display:
C:>blankflash>qflash -com5 -ramload MPRG8960.hex -mbn 33 MSM8960_bootloader
_singleimage.bin -v -o
Motorola qflash Utility version 1.3
COMPORT :COM3
RAMLOADER :MPRG8960.hex
type is 0x21
7 mbn file name MSM8960_bootloader_singleimage.bin type 33
verbose mode on
Motorola qflash dll version 1.6
RAMLOADER VERSION: PBL_DloadVER2.0
——————————————————
DEVICE INFORMATION:
——————————————————
Version : 0x8
Min Version : 0x1
Max Write Size: 0x600
Model : 0x90
Device Size : 0
Description : Intel 28F400BX-TL or Intel 28F400BV-TL
——————————————————
Using passed in packet size, changing from 0x600 -> 0x600
EXTENDED_LINEAR_ADDRESS_REC @ 0x2a000000
Write 65536 bytes @ 0x2a000000
100EXTENDED_LINEAR_ADDRESS_REC @ 0x2a010000
Write 11840 bytes @ 0x2a010000
100START_LINEAR_ADDRESS_REC @ 0x2a000000
No data read from USB. This may not be an error. Trying again…
No data read from USB. This may not be an error. Trying again…
No data read from USB. This may not be an error. Trying again…
No data read from USB. This may not be an error. Trying again…
No data read from USB. This may not be an error. Trying again…
Still no data, giving up!
dmss_go : failed to receive ACK
Error loading MPRG8960.hex into device