CISCO3925-CHASSIS V02

  1. Start the console session.

    Plug in serial cable to device from PC COM1 port
    Open PuTTY and select "Serial" connection type, leave baud rate (Speed) and other settings as default.
    Plug power into device and if a power button exists, turn it on.
  2. Access the Rommon prompt.

    Repeatedly press the Break key. Example output:
    Readonly ROMMON initialized program load complete, entry point: 0x4000000, size: 0x18fa0 monitor: command "boot" aborted due to user interrupt rommon 1 >
    TIP: If your keyboard does not have a Break key, in PuTTY right-click the titlebar for the dropdown menu -> Special Command -> Break.
  3. Bypass any configured login.

    Type the confreg command followed by a string value instruction to ignore the current configuration when booting up:
    rommon 1 > confreg 0x2142 You must reset or power cycle for new config to take effect
    Type the reset command:
    rommon 2 > reset System Bootstrap, Version 15.0(1r)M13, RELEASE SOFTWARE (fc1) Technical Support: http://www.cisco.com/techsupport Copyright (c) 2011 by cisco Systems, Inc. Total memory size = 1024 MB - DIMM0 = 512 MB, DIMM1 = 512 MB CISCO3925-CHASSIS with C3900-SPE100/K9 with 1048576 Kbytes of main memory Main memory is configured to 72/72(dimm 0/1) bit mode with ECC enabled
    The boot process should bring you to an initial configuration dialog prompt. Type n then the Enter key, and Enter again when prompted to get started:
    Would you like to enter the initial configuration dialog? [yes/no]: n Press RETURN to get started!
  4. Erase any log files, vlan data and all configuration settings.

    Type the enable command to enter privileged command mode, then the dir command, then the del command with * where necessary to match multiple filenames listed:
    Router>enable Router#dir Directory of flash0:/ 1 -rw- 66895008 Jan 28 2012 23:57:50 +00:00 c3900-universalk9- mz.SPA.151-4.M3.bin 2 -rw- 2903 Jan 29 2012 00:07:52 +00:00 cpconfig-39xx.cfg 3 -rw- 4781 Jan 29 2012 00:08:02 +00:00 vlan.dat 256507904 bytes total (189605212 bytes free) Router#del vlan.dat Delete filename [vlan.dat]? Delete flash0:/vlan.dat? [confirm]y Router#del *.cfg Delete filename [*.cfg]? Delete flash0:/cpconfig-39xx.cfg? [confirm]y
    Type the erase startup-config command, and confirm with y:
    Router#erase startup-config Erasing the nvram filesystem will remove all configuration files! Continue? [confirm]y[OK] Erase of nvram: complete
    TIP: You can verify vlan data and configuration is gone with the show vlans and show startup-config commands respectively:
    Router#show vlans No Virtual LANs configured. Router#show startup-config startup-config is not present
  5. Reboot the device and set it back to normal mode.

    Type the reload command and confirm with y:
    Router#reload Proceed with reload? [confirm]y *Oct 5 22:01:00.243: %SYS-5-RELOAD: Reload requested by console. Reload Reason: Reload Command.
    Send the router a Break command again as done in step 2, then at the rommon prompt type the confreg command followed by a different string value instruction to no longer ignore the configuration:
    rommon 1 > confreg 0x2102 You must reset or power cycle for new config to take effect
    Lastly type the reset command:
    rommon 2 > reset
  6. Copy all the output from the session into your records.

    Right-click PuTTY's titlebar, from that dropdown menu click on "Copy All to Clipboard"
    Open the file of record certifying the deconfiguration of this device and use CTRL V to paste all the output from PuTTY into that file. Formatting the text with a fixed-width font helps it look more readable.
  7. End the session.

    Turn off/unplug the device and close PuTTy.