1、开启TFTP server，并且保证设备和TFTP server可达。
2、上传镜像文件到ASA：
ciscoasa# copy tftp: disk0: >>>>拷贝镜像到ASA disk0
Address or name of remote host []? 192.168.111.2
Source filename []? asa917-20-k8.bin
Destination filename [asa917-20-k8.bin]? asa917-20-k8.bin
Accessing tftp://192.168.111.2/asa917-20-k8.bin...!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Writing file disk0:asa917-20-k8.bin…
27426816 bytes copied in 29.800 secs (945752 bytes/sec)
ciscoasa# dir >>>>查看目前镜像以及所剩的空间
Directory of disk0:/
3 drwx 2048 00:31:08 Jan 01 2008 log
6 drwx 2048 00:31:24 Jan 01 2008 crypto_archive
76 -rwx 0 00:31:28 Jan 01 2008 nat_ident_migrate
82 -rwx 2177 00:31:28 Jan 01 2008 8_2_5_0_startup_cfg.sav
10 drwx 2048 00:31:28 Jan 01 2008 coredumpinfo
83 -rwx 1225 00:31:28 Jan 01 2008 upgrade_startup_errors_200801010031.log
84 -rwx 25159680 00:51:48 Jan 01 2008 asa842-k8.bin
87 -rwx 27426816 01:43:56 Aug 28 2008 asa917-20-k8.bin
128573440 bytes total (75687936 bytes free)
3、验证完整性：（可选）
ciscoasa# verify disk0:asa917-20-k8.bin
Verifying file integrity of disk0:/asa917-20-k8.bin!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Embedded Hash MD5: 8c3f0c748f5b2f5a21242c038d56dd35
Computed Hash MD5: 8c3f0c748f5b2f5a21242c038d56dd35
CCO Hash MD5: 437b5297eca7d4284a16f9f25485506c
Signature Verified
Verified disk0:/asa917-20-k8.bin
4、修改启动镜像
ciscoasa(config)# boot system disk0:/asa917-20-k8.bin
5、查看启动镜像及顺序
ciscoasa# show bootvar
BOOT variable = disk0:/asa842-k8.bin;disk0:/asa917-20-k8.bin
Current BOOT variable = disk0:/asa842-k8.bin;disk0:/asa917-20-k8.bin
CONFIG_FILE variable =
Current CONFIG_FILE variable =
6、去掉之前的镜像或删除原镜像的启动路径（还是删除启动路径的好）
ciscoasa(config)# delete disk0:/asa842-k8.bin
Delete filename [asa842-k8.bin]?
Delete disk0:/asa842-k8.bin? [confirm]
ciscoasa(config)# dir
Directory of disk0:/
3 drwx 2048 00:31:08 Jan 01 2008 log
6 drwx 2048 00:31:24 Jan 01 2008 crypto_archive
77 -rwx 0 00:31:28 Jan 01 2008 nat_ident_migrate
84 -rwx 2177 00:31:28 Jan 01 2008 8_2_5_0_startup_cfg.sav
10 drwx 2048 00:31:28 Jan 01 2008 coredumpinfo
85 -rwx 1225 00:31:28 Jan 01 2008 upgrade_startup_errors_200801010031.log
87 -rwx 27426816 01:43:56 Aug 28 2008 asa917-20-k8.bin
=======================================
ciscoasa(config)# no boot system disk0:/asa842-k8.bin
ciscoasa# sho bootvar
BOOT variable = disk0:/asa842-k8.bin;disk0:/asa917-20-k8.bin >>>发现还是存在
Current BOOT variable = disk0:/asa917-20-k8.bin
CONFIG_FILE variable =
Current CONFIG_FILE variable =
ciscoasa# wr memory >>>保存后生效
Building configuration...
Cryptochecksum: 489e5c00 3ea0a2d8 4da33988 ff85739a
2809 bytes copied in 1.260 secs (2809 bytes/sec)
[OK]
ciscoasa# show bootvar
BOOT variable = disk0:/asa917-20-k8.bin
Current BOOT variable = disk0:/asa917-20-k8.bin
CONFIG_FILE variable =
Current CONFIG_FILE variable =
7、重启设备
ciscoasa(config)# reload
8、查看版本
ciscoasa# sh version
Cisco Adaptive Security Appliance Software Version 9.1(7)20
Compiled on Thu 02-Nov-17 18:27 by builders
System image file is "disk0:/asa917-20-k8.bin"