使用的时TI官方C6748开发板，开机boot切换到UART2模式，上电后在PC端串口中能看到BOOTME信息，但在执行擦除flash时一直卡在waiting for SFT on the OMAP-L138这里，请问这时什么问题？怎么解决？盼指教，谢谢！
具体过程如下：
C:\cygwin\home\tzheng\OMAP-L138_FlashAndBootUtils_2_40\OMAP-L138\GNU>sfh_OMAP-L1
38.exe -erase -targetType C6748 -flashType NAND -p COM3 -v
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TI Serial Flasher Host Program for OMAP-L138
(C) 2012, Texas Instruments, Inc.
Ver. 1.67
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[TYPE] Global erase
[TARGET] C6748
[DEVICE] NAND
[NAND Block] 1
Attempting to connect to device COM3...
Press any key to end this program at any time.
(AIS Parse): Read magic word 0x41504954.
(AIS Parse): Waiting for BOOTME... (power on or reset target now)
(AIS Parse): BOOTME received!
(AIS Parse): Performing Start-Word Sync...
(AIS Parse): Performing Ping Opcode Sync...
(AIS Parse): Processing command 0: 0x58535901.
(AIS Parse): Performing Opcode Sync...
(AIS Parse): Loading section...
(AIS Parse): Loaded 19808-Byte section to address 0x11800000.
(AIS Parse): Processing command 1: 0x58535901.
(AIS Parse): Performing Opcode Sync...
(AIS Parse): Loading section...
(AIS Parse): Loaded 1364-Byte section to address 0x11804D60.
(AIS Parse): Processing command 2: 0x58535901.
(AIS Parse): Performing Opcode Sync...
(AIS Parse): Loading section...
(AIS Parse): Loaded 20-Byte section to address 0x118052F0.
(AIS Parse): Processing command 3: 0x58535901.
(AIS Parse): Performing Opcode Sync...
(AIS Parse): Loading section...
(AIS Parse): Loaded 16-Byte section to address 0x11805304.
(AIS Parse): Processing command 4: 0x58535906.
(AIS Parse): Performing Opcode Sync...
(AIS Parse): Performing jump and close...
(AIS Parse): AIS complete. Jump to address 0x11804620.
(AIS Parse): Waiting for DONE...
(AIS Parse): Boot completed successfully.
Waiting for SFT on the OMAP-L138...
