请参照一下步楱操作：
Rommon #9> interface giga0/0 {choose the interface where the TFTP server
will be located at}
GigabitEthernet0/0
Link is UP
MAC Address: 0018.1900.29ec
Rommon #10> address 10.198.28.5 {interface IP address}
Rommon #11> server 10.198.28.28 {TFTP server IP address}
Rommon #12> file asa803-k8.bin
Rommon #13> tftp
ROMMON Variable Settings:
ADDRESS=10.198.28.5
SERVER=10.198.28.28
GATEWAY=0.0.0.0
PORT=GigabitEthernet0/0
VLAN=untagged
IMAGE=asa803-k8.bin
CONFIG=
LINKTIMEOUT=20
PKTTIMEOUT=4
RETRY=20
Tftp
asa803-k8.bin@10.198.28.28!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
ASA此时会自动重启.
Then you need to copy the image to flash:
ASA5510#copy tftp disk0:
Enter the remote host IP address where you have the TFTP server loaded at.
Enter the ASA binary filename: asa803-k8.bin.
Type yes.
-Issue the following command to set "asa803-k8.bin" as the boot image.
ASA5510(config)# boot system disk0:/asa803-k8.bin
ASA5510# write memory
-Reload.
