我使用sfh_OMAP-L138.exe串口烧写工具来烧写UBL、UBOOT时，在擦除的过程中总是停止在Waiting for SFT on the OMAP-L138...这，具体信息如下：
C:\temp>sfh_OMAP-L138.exe -erase -targetType OMAPL138 -flashType NAND -P COM4
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TI Serial Flasher Host Program for OMAP-L138
(C) 2010, Texas Instruments, Inc.
Ver. 1.67
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[TYPE] Global erase
[TARGET] OMAPL138
[DEVICE] NAND
Attempting to connect to device COM4...
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 13512-Byte section to address 0x80000000.
(AIS Parse): Processing command 1: 0x58535901.
(AIS Parse): Performing Opcode Sync...
(AIS Parse): Loading section...
(AIS Parse): Loaded 1360-Byte section to address 0x800034C8.
(AIS Parse): Processing command 2: 0x58535906.
(AIS Parse): Performing Opcode Sync...
(AIS Parse): Performing jump and close...
(AIS Parse): AIS complete. Jump to address 0x80000000.
(AIS Parse): Waiting for DONE...
(AIS Parse): Boot completed successfully.
Waiting for SFT on the OMAP-L138...
请问这是什么原因，怎么解决呢？
