Guest

Cisco Catalyst 8500 Series Multiservice Switch Routers

Recovering from a Corrupted or Lost Cisco IOS Image on LS1010 and Catalyst 8500 Switches

Document ID: 10465

Updated: Nov 15, 2007

   Print

Introduction

This document discusses how to recover from a corrupted or lost Cisco IOS® software image on LS1010 and Catalyst 8500 series of ATM switches.

The Loading and Maintaining System Images chapter of the Cisco IOS configuration guides provides step-by-step instructions for file system management for all platforms that run Cisco IOS.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

This document is not restricted to specific software and hardware versions.

Conventions

For more information on document conventions, refer to the Cisco Technical Tips Conventions.

Recovery Methods

Normally, if your ATM switch comes up in ROMMON mode, you can use the boot command to tell the switch which image to load. Note that while the ROMMON command-line interface (CLI) lists a dnld command, the LS1010 does not support xmodem download. The dnld command is left over from the IOS branch from which it was ported.

rommon 10 > ? 
alias               set and display aliases command 
boot                boot up an external process 
break               set/show/clear the breakpoint 
confreg             configuration register utility 
cont                continue executing a downloaded image 
context             display the context of a loaded image 
dev                 list the device table 
dir                 list files in file system 
dis                 disassemble instruction stream 
dnld                serial download a program module 
frame               print out a selected stack frame 
help                monitor builtin command help 
[output omitted]

If the image in bootflash becomes corrupted and your ATM switch goes into ROMMON, you can manually boot from a network file. Use a command such as boot <file path> <tftp server ip address>.

The only other recovery method is to use a PCMCIA card. Cisco platforms support three Flash memory file system types named Class A, Class B and Class C. The LS1010 and Catalyst 8500 series use a Class A file system. If you do not have a PCMCIA card in your ATM switch, you can use a card from one of these platforms, which also use a Class A file system and formatting:

  • Route Switch Module (RSM) from the Catalyst 5000

  • GSR Route Processor (GRP)

  • Cisco 7500 series Route Switch Processor (RSP) 2, 4, or 8

  • RSP7000

Use the PCMCIA Filesystem Compatibility Matrix to confirm that you use a PC card from a platform with the same file system.

The PCMCIA card for your ATM switch can be formatted in other RSP-based systems or in a working ATM switch. Format a PCMCIA card on a working system and copy the appropriate image to it via a command such as copy tftp slot0:. Then move the PC card back to the ATM switch's PC card slot.

Use these steps to boot an image from a PCMCIA card slot.

  1. Execute the dev command to determine the device names of the PCMCIA slots.

    rommon 18 > dev 
    Devices in device table: 
            id  name 
    bootflash:  boot flash 
        slot0:  PCMCIA slot 0 
        slot1:  PCMCIA slot 1 
        eprom:  eprom
  2. Execute the dir command to view the files on your PCMCIA card.

    rommon 19 > dir 
    usage: dir <device> 
    rommon 20 > dir slot0: 
             File size         Checksum   File name 
       401756 bytes (0x80335c) 0x2a290d95 cat8540m-wp-mz_120-10_W5_18c.bin
  3. Execute the boot command and specify a PC card slot number and a Cisco IOS image name.

    rommon 21 > boot slot0:cat8540m-wp-mz_120-10_W5_18c.bin 
    Self decompressing the image : ######################
    ##################################################### 
    ##################################################### 
    ##################################################### 
    ################################################ 
    
       PRIMARY CPU: 
    Booting on Mar 23 2001 13:10:06 
    
     Cat8540 Diagnostics V1.4, Dated Aug 19 2000 00:54:12 
     Model ACTIVE CPU-Card, Serial# MIC025006YD, H/W V5.5 
     Copyright (c) Cisco Systems Inc.  1999 
    
    ...................................... 
    
    Power-on Diagnostics Passed. 
    Reading cubi version..Done

    In rare cases, you may see these error messages:

    rommon 20 > dir slot0: 
    PCMCIA slot0 device is not initialized 
    open: read error...requested 0x4 bytes, got 0x0 
    trouble reading device magic number 
    dir: cannot open device "slot0:"

These messages indicate that ROMMON detected a bad or unexpected checksum when you executed the directory command. To fix the problem:

  • Read the PC card in another system.

  • Swap the PC card with a known working card from another system.

  • If necessary, reformat the card on a working system and copy the appropriate image to it via a command such as copy tftp slot0:. Then move the PC card back to the ATM switch's PC card slot.

Class A File System Commands

The methods used for erasing, deleting, and recovering files depend on the class of the file system. Class A file systems support these file management commands:

  • delete - "Marks" files as deleted, but the files still occupy space in Flash memory. Use the undelete command to recover these files later.

  • squeeze - Permanently removes all of the files marked "deleted" from the specified Flash memory device. These files can no longer be recovered. The squeeze operation can take as long as several minutes if it needs to erase and rewrite most of the Flash memory space on a PCMCIA card.

  • format - Erases all of the files on a Flash device.

  • verify - Recomputes and verifies the checksum of a file in Flash memory.

Related Information

Updated: Nov 15, 2007
Document ID: 10465