在项目实施和故障排除过程中，经常会遇到路由器IOS BUG无法正常启动,CF卡故障，个别无良网管操作造成配置丢失flash被写入莫名其妙的东西。利用好设备自带的USB能帮助我们快速进行此类故障恢复。

第一种情况

在设备良好运行的情况下，如果你有新增一批同型号交换机，或者路由器，那用usb进行IOS的升级同步是非常好用的。

准备一个u盘，移动硬盘也行，试验设备CISCO 1841

将USB设备插入

console显示出检测到usb设备

 

*Aug 24 06:17:43.655: %USB_HOST_STACK-6-USB_DEVICE_CONNECTED: A Full speed USB device has been inserted in port 0.
*Aug 24 06:17:44.299: %USBFLASH-5-CHANGE: usbflash0 has been inserted!

A#format ?
  flash:        Filesystem to be formatted

---------显示出usb设备情况，因为我插的是移动硬盘分了3个区，所以显示如下
  usbflash0:    Filesystem to be formatted
  usbflash0:0:  Filesystem to be formatted
  usbflash0:1:  Filesystem to be formatted

IOS放在移动硬盘的第一个盘中，所以

A#dir usbflash0:
Directory of usbflash0:/

    1  drw-           0   Aug 9 2007 20:57:48 +00:00  System Volume Information
  266  drw-           0  Aug 11 2010 17:45:34 +00:00  gG
 1051  -rw-    14452703  Aug 13 2010 16:04:34 +00:00  VanDyke.SecureCRT.v6.5.3.zip
 1052  -rw-    44880216  Aug 24 2010 05:53:06 +00:00  c1841-adventerprisek9-mz.151-2.T1.bin
 1053  drw-           0  May 12 2010 22:15:16 +00:00  $RECYCLE.BIN

21465661440 bytes total (19124568064 bytes free)


从移动硬盘中COPY IOS

A#copy usbflash0: fl
A#copy usbflash0: flash:
Source filename []? c1841-adventerprisek9-mz.151-2.T1.bin
Destination filename [c1841-adventerprisek9-mz.151-2.T1.bin]?
Copy in progress...CCCCCCCCCCCCCCCCCCCCCCCCC省略

CCCCCCCCCCCCCCCC
44880216 bytes copied in 121.780 secs (368535 bytes/sec)

检查一下看FLASH

A#dir
Directory of flash:/

    1  -rw-    44880216  Aug 24 2010 06:24:08 +00:00  c1841-adventerprisek9-mz.151-2.T1.bin

64000000 bytes total (19116032 bytes free)
A#

第二种情况，设备无法正常开机，进入rommon模式需要手动引导载入IOS，这种情况下usb的优势就体现出来，大家再也不用xmodem(为了提高速度还要改波特率）或者接反线折腾半天了，直接可以从usb启动，启动完再把ios拷贝进设备。

我们来看，设备开机就进入rommon
rommon 2 > dev      ----------看有无支持usb
Devices in device table:
        id  name
    flash:  external compact flash    
bootflash:  boot flash                
usbflash0:  usbflash0                 
    eprom:  eprom          

让设备从usb载入IOS启动

           
rommon 3 > boot usbflash0:c1841-adventerprisek9-mz.151-2.T1.bin

program load complete, entry point: 0x8000f000, size: 0xcb80
program load complete, entry point: 0x8000f000, size: 0xcb80

program load complete, entry point: 0x8000f000, size: 0x2accfb8
Self decompressing the p_w_picpath : ############################################################################################################################################################################################################################################################## [OK]

Smart Init is enabled
smart init is sizing iomem
  ID            MEMORY_REQ         TYPE
                0X003AA110 public buffer pools
                0X00211000 public particle pools
                0X00020000 Crypto module pools
                0X000021B8 Onboard USB

If any of the above Memory Requirements are
"UNKNOWN", you may be using an unsupported
configuration or there is a software problem and
system operation may be compromised.

Allocating additional 13997571 bytes to IO Memory.
PMem allocated: 245366784 bytes; IOMem allocated: 23068672 bytes

%C3600-3-SLOTS: Number of slots in chassis is undefined.
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
[email protected].

------------------------------------------------------------------------------------------------

检测到USB并开始从USB载入IOS

--------------------------------------------------------------------------------------------------
%×××_HW-6-INFO_LOC: Crypto engine: onboard 0  State changed to: Initialized
%×××_HW-6-INFO_LOC: Crypto engine: onboard 0  State changed to: Enabled Installed p_w_picpath archive

%USB_HOST_STACK-6-USB_DEVICE_CONNECTED: A Full speed USB device has been inserted in port 0.
%USBFLASH-5-CHANGE: usbflash0 has been inserted!
%SYS-6-BOOT_MESSAGES: Messages above this line are from the boot loader.

program load complete, entry point: 0x8000f000, size: 0x2accfb8后面略

如果遇到CF卡损坏而且暂时没有CF可供使用时，大家可以弄个u盘直接插在设备上面

在设备里面配置

boot system usbflash0：xxxxxx.bin

当然在这样的话你的usb得一直插着，如果之后使用CF卡，记得把上面的命令拿掉。