学员提问：
思科3640路由器出故障了，估计是IOS丢了。今天尝试恢复IOS，从网上下了ios恢复出错。
代码如下：
rommon 2 > xmodem -r
Do not start the sending program yet...
Invoke this application only for disaster recovery.
Do you wish to continue? y/n [n]: y
Ready to receive file ...
开始 xmodem 传输。 按 Ctrl+C 取消。
Transferring c3640-is-mz.124-10.bin...
100% 27206 KB 4 KB/s 01:51:37 2 Errors
Download Complete!
program load complete, entry point: 0x80008000, size: 0x1a919d8
Self decompressing the image :
Error : Uncompression of the image failed.
invalid compressed data--format violated
Error : zip decompress failed
*** System received a Software forced crash ***
signal= 0x17, code= 0x7, context= 0x8000eb60
PC = 0x800080d4, Cause = 0x20, Status Reg = 0x3041f003
System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
Copyright (c) 1999 by cisco Systems, Inc.
C3600 processor with 65536 Kbytes of main memory
Main memory is configured to 64 bit mode with parity disabled
lseek out of bounds
getdirent: lseek error
boot: cannot determine first file name on device "flash:"
System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
Copyright (c) 1999 by cisco Systems, Inc.
C3600 processor with 65536 Kbytes of main memory
Main memory is configured to 64 bit mode with parity disabled
PCMCIA Slot0: No Card Present
System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
Copyright (c) 1999 by cisco Systems, Inc.
C3600 processor with 65536 Kbytes of main memory
Main memory is configured to 64 bit mode with parity disabled
PCMCIA Slot1: No Card Present
System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
Copyright (c) 1999 by cisco Systems, Inc.
C3600 processor with 65536 Kbytes of main memory
Main memory is configured to 64 bit mode with parity disabled
lseek out of bounds
getdirent: lseek error
boot: cannot determine first file name on device "flash:"
System Bootstrap, Version 11.1(20)AA2, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
Copyright (c) 1999 by cisco Systems, Inc.
C3600 processor with 65536 Kbytes of main memory
Main memory is configured to 64 bit mode with parity disabled
rommon 1 > dir flash:
File size Checksum File name
lseek out of bounds
getdirent: lseek error
rommon 2 >
rommon 2 > lseek error
捷盈讲师及学员解答：
你从xmodem恢复IOS出现了error，在恢复IOS的过程中，不能出现丢包的，丢包会造成上传的IOS有问题，看情况需要重新恢复，最好先确保你找的IOS没有问题。