當ASA鏡像文件丟失時：
系統恢復
rommon #0> address x.x.x.x
rommon #1> server x.x.x.x
rommon #2> gateway x.x.x.x
rommon #2> interface GigabitEthernet0/1
GigabitEthernet0/1
MAC Address: 000f.f775.4b54
rommon #3> file asa821-k8.bin
查看：rommon #2>set
開始下載：rommon #5> tftpdnld
當ASA密碼丟失時：
密碼恢復
1、使用BREAK or ESC進入ROMMON模式
2、修改confreg
rommon #0> confreg
Current Configuration Register: 0x00000001
Configuration Summary:
boot default image from Flash
Do you wish to change this configuration? y/n [n]:y//修改寄存器值
enable boot to ROMMON prompt? y/n [n]:
enable TFTP netboot? y/n [n]:
enable Flash boot? y/n [n]:
select specific Flash image index? y/n [n]:
disable system configuration? y/n [n]: y//不加載配置
go to ROMMON prompt if netboot fails? y/n [n]:
enable passing NVRAM file specs in auto-boot mode? y/n [n]:
disable display of BREAK or ESC key prompt during auto-boot? y/n [n]:
Current Configuration Register: 0x00000040
3、重啓設備rommon #1> boot
4、ciscoasa# copy startup-config running-config//之前的初始配置覆蓋當前配置
5、修改密碼
Chicago# config terminal
Chicago(config)# passwd C1$c0123
Chicago(config)# enable password C1$c0123
5、修改寄存器
Chicago(config)# config-register 0x1
6、保存
write