ASA 5510密码恢复：
1.重启防火墙出现
Use BREAK or ESC to interrupt boot.
Use SPACE to begin boot immediately.
2.进入rommon模式，然后修改寄存器
rommon #1> confreg
Current Configuration Register: 0x00000001-------------当前asa的寄存器值
Configuration Summary:
boot default image from Flash
Do you wish to change this configuration? y/n [n]: y---------------是否改变现有配置
enable boot to ROMMON prompt? y/n [n]: y
select specific Flash image index? y/n [n]: n
disable system configuration? y/n [n]: y --------重要----------是否关闭系统当前的配置
go to ROMMON prompt if netboot fails? y/n [n]: y
enable passing NVRAM file specs in auto-boot mode? y/n [n]: y
disable display of BREAK or ESC key prompt during auto-boot? y/n [n]: n
Current Configuration Register: 0x00102040---------------------修改后的寄存器值
Configuration Summary:
boot ROMMON
ignore system configuration
load ROMMON if netboot fails
pass NVRAM file specs in auto-bootloader mode
Update Config Register (0x102040) in NVRAM…
3.重启asa
rommon #2> boot
4.copy 原有配置
ciscoasa(config)# copy startup-config running-config
5，修改密码，并保持
6.寄存器立刻改回原值，然后重启。
Rack46ASA2(config)# config-register 0x01