Recover a Catalyst Switch from Corrupt or Missing Software Image
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Introduction
This document explains on how to recover from a corrupt or missing
software image on the Cisco Catalyst Switches. This procedure applies to the
2900XL, 2940, 2950, 2970, 3500XL, 3550, 3560, and 3750 models of Cisco Catalyst
switches.
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Requirements
To perform the steps described in this document, you need to have these
items:
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Physical access to the switch
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A Windows PC with terminal-emulation software, such as
HyperTerminal
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A console cable or a rolled cable with an adapter. Refer to
Cable
Descriptions for further information.
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A new Cisco IOS software image provided to you by the
SMB
Technical Assistance Center (SMB TAC). If you do not have a new image,
contact the
SMB
TAC for assistance. The new software image is required, if your switch
software is corrupted or missing.
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Recover the switch from ROMmon mode or switch: prompt
The error loading flash message
indicates that, Flash is unable to load the current image. This message appears
when the image is corrupt or incorrect, or is missing from Flash. If the system
is unable to load a software image in Flash, the system loads the boot helper
and brings up a switch: prompt. Otherwise, the
switch is in a continuous boot cycle.
Connect to the Switch
You need a console access to your switch in order to boot the switch
with a valid software image. To set up console access to the switch, follow
these steps:
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Connect the RJ-45 connector of the console cable into the console
port on the rear panel of the switch.
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Connect the DB-9 connector to the PC serial
port.
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On your PC, choose Start >
Programs > Accessories >
Communications > HyperTerminal to open
HyperTerminal. For additional information on how to connect a terminal to the
console port, refer to
Create a
HyperTerminal Connection.
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Create a connection with these terminal settings:
Click OK and press Enter.
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The HyperTerminal window displays a command-line
prompt.
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Go to the Verify the Software Image in
Flash and Attempt to Manually Boot the Switch section, if the switch
command line displays switch: prompt. Otherwise,
follow the steps in the Bring up the switch into boot
loader or switch: prompt section.
Bring up the switch into Boot Loader or switch: prompt
If the switch stucks in a continuous boot cycle, bring up the switch
into boot loader or switch: prompt. To bring the
switch into the boot loader, follow these steps:
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Unplug the power cable.
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Hold down the Mode button located on the left side of the front
panel while you reconnect the power cord to the switch. For the Catalyst 2900XL
switch, release the Mode button for one or two seconds after the LED over Port
1x is no longer illuminated. The switch: prompt
appears.
Note: You must release the mode button carefully.
Review this table to determine when to release the Mode button for
your switch.
Model Number
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LED Behavior
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2940, 2950
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Release the Mode button approximately after 5 seconds when
the Status (STAT) LED turns off. When you release the Mode button, the SYST LED
blinks amber.
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2960, 2970
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Release the Mode button when the SYST LED blinks amber and
then turns solid green. When you release the Mode button, the SYST LED blinks
green.
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3550
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Release the Mode button when the LED above Port 1x turns
off.
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3560, 3750
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Release the Mode button approximately after 15 seconds when
the SYST LED turns solid green. When you release the Mode button, the SYST LED
blinks green.
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Type flash_init and press Enter
at the switch: prompt.
switch: flash_init
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Type load_helper and press Enter
to load any boot helper images.
switch: load_helper
Verify the Software Image in Flash and Attempt to Manually Boot the Switch
To verify the software image in flash and attempt to manually boot the
switch, follow these steps:
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Type dir flash: and press Enter
to view the contents of the flash file system.
The contents of the switch file system must look similar to this
example:
switch: dir flash:
Directory of flash:/
3 -rwx 1809152 <date> c2900XL-c3h2s-mz-120.5-XU.bin
4 -rwx 676 <date> vlan.dat
5 -rwx 1278 <date> config.text
6 -rwx 322 <date> env_vars
1799168 bytes available (1813504 bytes used)
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Verify that the image in Flash is the correct image for the
platform. Check the software image file name from the command line output of
dir flash: with the hardware model number located in front of
the switch.
Note: Go to the Copy a New Software Image from
ROM Monitor section, if the software image present is incorrect for the
switch, or if the image is missing.
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Boot the software image manually, if the software image in Flash is
correct.
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Type boot flash:
<filename>
where
filename
is your software image name
present in the flash.
switch: boot flash: c2900XL-c3h2s-mz-120.5-XU.bin
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Go to the Change and Verify Boot
Configuration section, if the system boots correctly and does not return
to the switch: prompt. Otherwise, follow the
steps in the Copy a New Software Image from ROM
Monitor section, if the system still fails to load the image
correctly.
Copy a New Software Image from ROM Monitor
To copy a new software image from a ROM Monitor, follow these
steps:
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Download the new Cisco IOS-only image provided to you by the
SMB
Technical Assistance Center (SMB TAC). If you do not have a new image,
contact the
SMB
TAC for assistance.
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Type dir flash: and press Enter
to check the size of the IOS image file to be loaded in flash.
switch: dir flash:
Directory of flash:/
3 -rwx 1809152 <date> c2900XL-c3h2s-mz-120.5-XU.bin
4 -rwx 676 <date> vlan.dat
5 -rwx 1278 <date> config.text
6 -rwx 322 <date> env_vars
1799168 bytes available (1813504 bytes used)
Note: The last line in the output shows the available memory in
flash.
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Delete the existing image(s) in Flash to make space for a new
image, if the size of the file to be loaded is larger than the available memory
capacity in flash.
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Type delete flash:
filename
and press Enter
to delete the file from flash memory where
filename
is the name of the file to be
deleted.
switch: delete flash: c2900XL-c3h2s-mz-120.5-XU.bin
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Type copy xmodem: flash:
filename
and press Enter
where
filename
is the name of the new
file to be loaded into flash.
switch: copy xmodem: flash:c2900xl-c3h2s-mz.120-5.WC10.bin
CCC..........................................................................
(BEGIN XMODEM DOWNLOAD ON TERMINAL SOFTWARE NOW)
Note: You must start the XMODEM download process within three seconds.
Otherwise, the switch times out the XMODEM copy.
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On the menu bar of the HyperTerminal, click
Transfer > Send File.
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In the Send File window, make these changes:
Click Send to start the file transfer
process.
The Xmodem file transfer starts in the Xmodem file
send window.
Note: On successful download of the IOS image in flash, this message
appears:
File "xmodem:" successfully copied to "flash:c3500XL-c3h2s-mz.120-5.1.XP.bin".
Contact the
SMB
Technical Assistance Center (SMB TAC), if the image download is not
successful.
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Type boot flash:
filname
to boot your switch with the new
image. Use the boot flash:
filname
command where
filename
is the name of the file you
download.
switch: boot flash: c2900xl-c3h2s-mz.120-5.WC10.bin
Change and Verify Boot Configuration
To change and verify the boot configuration, follow these
steps:
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Type enable and press Enter at
the switch> prompt to enter the enable
mode.
switch>enable
switch#
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Type configure terminal and press
Enter at the switch> prompt
to enter the configuration mode.
switch#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)#
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Type boot system flash:
filename
and press Enter
where
filename
is your software image
name present in the flash.
switch(config)#boot system flash:c2900xl-c3h2s-mz.120-5.WC10.bin
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Type write memory and press Enter
to write the running configuration to the startup
configuration.
Switch#write memory
Building configuration...
Compressed configuration from 4128 to 1219 bytes[OK]
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Exit the terminal software.
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Next Step
You have completed Software Image recovery for your Catalyst Switch.
To configure your switch, proceed to
Download and
Install Cisco Network Assistant.
To make further changes to your switch, refer to the
Switch
Support Page.
To configure other devices in your network, refer to the
Configuration
Overview Page.
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Related Information
