Chapter 37 Troubleshooting - Cisco Catalyst 3550 series Software Configuration Manual

Using Recovery Procedures
Recovering from Corrupted Software
Switch software can be corrupted during an upgrade, by downloading the wrong file to the switch, and
by deleting the image file. In all of these cases, the switch does not pass the power-on self-test (POST),
and there is no connectivity.
This procedure uses the XMODEM protocol to recover from a corrupt or wrong image file. There are
many software packages that support the XMODEM protocol, and this procedure is largely dependent
on the emulation software you are using.
Follow these steps to recover from corrupted software:
Step 1 Connect a PC with terminal-emulation software supporting the XMODEM protocol to the switch
console port.
Step 2 Set the line speed on the emulation software to 9600 baud.
Unplug the switch power cord.
Step 3
Press the Mode button, and at the same time, reconnect the power cord to the switch.
Step 4
You can release the Mode button a second or two after the LED above port 1X turns off. Several lines
of information about the software appear along with instructions:
The system has been interrupted prior to initializing the flash file system. The following
commands will initialize the flash file system, and finish loading the operating system
software#
flash_init
load_helper
boot
Step 5 Initialize the Flash file system:
switch# flash_init
Step 6 If you had set the console port speed to anything other than 9600, it has been reset to that particular
speed. Change the emulation software line speed to match that of the switch console port.
Step 7 Load any helper files:
switch# load_helper
Step 8 Start the file transfer by using the XMODEM protocol.
switch# copy xmodem: flash:image_filename.bin
After the XMODEM request appears, use the appropriate command on the terminal-emulation software
Step 9
to start the transfer and to copy the software image into Flash memory.
Recovering from a Lost or Forgotten Password
An end user with physical access to the switch can recover from a lost password by interrupting the boot
process during power-on and by entering a new password. This is the default configuration for Catalyst
3550 switches.
Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 37 Troubleshooting
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