1. Boot-Prozess unterbrechen, z.B. auf 4221 mit Ctrl-C
2. rommon 1> confreg 0x2142
3. rommon 2> reset

Rücksetzen des Konfigurationsregisters:

1. Router# show version
2. Router# configure terminal
3. Router(config)# config-register 0x2102

Power-on the switch and hold down the mode button located on the left side of the front panel:

Model 2960, 2970 - 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 fast.

Model 3560, 3750 - release the Mode button after approximately 15 seconds when the SYST LED turns solid green. When you release the Mode button, the SYST LED blinks green fast.

The following output should be seen on the console:

The system has been interrupted prior to initializing the flash file system to finish 
loading the operating system software:

   flash_init
   load_helper
   boot

switch:

Issue the flash_init command:

  switch: flash_init 

Issue the load_helper command:

  switch: load_helper

Show the flash content with the dir flash: command:

Note: Make sure to type a colon „:“ after the dir flash.

  switch: dir flash:

Rename the config-file config.text

  switch: rename flash:config.text flash:config.old 
  !--- The config.text file contains the passwords ---!

Issue the boot command to boot the system.

  switch: boot 

Abort the initial configuration dialog by answering „n“ at the prompt.

At the switch prompt, type en to enter enable mode.

  Switch>en 
  Switch#

Type rename flash:config.old flash:config.text to rename the configuration file with its original name.

  Switch#rename flash:config.old flash:config.text 

Copy the configuration file into memory:

  Switch#copy flash:config.text system:running-config 
  Destination filename [running-config]? !--- Press Return or Enter. 1131 bytes copied in 0.760 secs 
  Sw1#

The configuration file is now reloaded.

Overwrite the current passwords that you do not know. Choose a strong password.

Note: Overwrite the passwords which are necessary. You need not overwrite all of the mentioned passwords.

  Sw1# conf t !--- To overwrite existing secret password 
  Sw1(config)#enable secret  !--- To overwrite existing enable password 
  Sw1(config)#enable password  !--- To overwrite existing vty password 
  Sw1(config)#line vty 0 15 
  Sw1(config-line)#password  
  Sw1(config-line)#login !--- To overwrite existing console password 
  Sw1(config-line)#line con 0 
  Sw1(config-line)#password 

Write the running configuration to the configuration file with the write memory command.

  Sw1#write memory