It’s been a while since I had to use rommon.

This site has a good write up on resetting a Cisco ASA. I used it on an ASA5506.

The gist of it:

  1. Boot into rommon
  2. confreg (answer no)
  3. confreg 0x41
  4. boot
  5. enable (blank password)
  6. write erase
  7. conf t
  8. config-register 0x01
  9. exit
  10. write
  11. reload