How-to Factory-Reset 

Cisco ASA 5500 and 5500X Series

 

 

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Step 1 Connect to console port or Out-of-Band management and make sure that console output given.

Step 2 Power cycle your ASA

Step 3 Press ESC when Use BREAK or ESC to interrupt boot. appears during boot process.

Gratulations You’re in rommon now:
rommon #0>

Step 4 Enter the following command to rommon to bypass the startup conf – also needed for ASA Password Recovery
rommon #1> confreg 0x41

Step 5 At the prompt enter Y es to save the configuration and continue.

Step 6 Type the boot command to rommon:
rommon #2>boot

Your ASA is booting to last boot system image in your configuration.

Step 7 Login to ASA and delete configuration – Leave Password blank and just press enter after typing enable
ciscoasa>enable
ciscoasa#write erase

Step 8 Set Configuration Register to default 0x01
ciscoasa#configure terminal
ciscoasa(config)#config-register 0x01
ciscoasa(config)#write
ciscoasa(config)#exit

Step 9 Reload ASA
ciscoasa#reload

Your Appliance will start with factory settings after next reload. Due to non bootvar is set, your ASA will start with the first image in the flash: