Recovering from a corrupt IOS image

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This is a bit of nastiness! You have a switch that refuses to boot. When you watch what's happening on the console you see errors like this: 

 Error loading "flash:c3750-k9-mz.122-44.se2.bin"
 
 Interrupt within 5 seconds to abort boot process.
 Boot process failed...
 
 switch:

You have a corrupt IOS image! To recover you will need Microsoft Windows HyperTerminal to perform an xmodem transfer of a new IOS image to the switch (obviously you can use other terminal emulators etc, but you'll get no help from me :-). This method has been tested with a Cisco 3750G. You can see more specific info for different switch models here.

1. Connect to the switch with HyperTerminal with these the settings: 

 Baud: 9600
 Data bits: 8
 Parity: None
 Stop bits: 1
 Flow control: None

2. If the switch is not already at the switch: prompt, remove the power cord. Hold down the MODE button on the front of the switch and re-insert the power cord. Wait until the SYST light is flashing away and let go of the MODE button.

3. You should be at the switch: prompt. Type the following commands: 

 switch: flash_init
 switch: load_helper

4. List the contents of the switches flash memory 

 switch: dir flash:
 Directory of flash:/
 
 2    -rwx  10761792  <date>               c3750-k9-mz.122-44.se2.bin
 3    -rwx  676       <date>               vlan.dat
 4    -rwx  7807      <date>               config.backup
 83   -rwx  98        <date>               private-config.text
 86   -rwx  1048      <date>               multiple-fs
 
 5113856 bytes available (10885120 bytes used)

5. If there is no room in flash for another IOS image, delete the old one: 

 switch: delete flash:c3750-k9-mz.122-44.se2.bin
 Are you sure you want to delete "flash:c3750-k9-mz.122-44.se2.bin" (y/n)?y
 File "flash:c3750-k9-mz.122-44.se2.bin" deleted

6. To speed the xmodem transfer up, change the Baud rate of the switch 

 switch: set BAUD 115200

You will lose access to the console, but a restart of the HyperTerminal session with a new Baud rate of 115200 will fix this!

7. At the switch: prompt, begin the xmodem transfer of the new IOS image: 

 switch: copy xmodem: flash:imagefilename
 Begin the Xmodem or Xmodem-1K transfer now...
 CCC
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