Cisco ASA 5500 and 5500X Series
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:
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:
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
Step 8 Set Configuration Register to default 0x01
Step 9 Reload ASA
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: