求助！关于JTAG口烧写bootloader问题！

我用JTAG口烧写bootloader，出现以下问题：
PLATFORM SELECTION:
Processor = PXA27X
Development System = Mainstone
Data Version = 1.00.002

error,failed to read device ID
check cable and power
ACT:1111 11111111111111 111111111111 1
EXP:**** 1001001001100101 0000001001 1

failed to read device ID for this Platform

出现以上问题我无法烧写FLASH，请有过该问题解决经验的前辈指点，不胜感激，谢谢！