1、首先确认 Switch Image 状态：

XCM8810.2 # show switch

Slot:                                                MSM-A *                              MSM-B
                                                ------------------------             ------------------------
Current State:                               MASTER                             BACKUP (In Sync)

Image Selected:                            primary                             primary
Image Booted:                              primary                             primary
Primary ver:                                  12.4.4.10                            12.4.4.10
Secondary ver:                            12.4.4.10                            12.4.4.10

Config Selected:                           primary.cfg                       primary.cfg
Config Booted:                              primary.cfg                       primary.cfg

primary.cfg                              Created by NETGEAR version 12.4.4.10
                              309408 bytes saved on Tue Sep 4 16:25:39 2012

2、开启PC上的TFTP Server软件并确保Switch 与PC之间可达：

XCM8810.3 # ping 10.45.1.51
Ping(ICMP) 10.45.1.51: 4 packets, 8 data bytes, interval 1 second(s).
16 bytes from 10.45.1.51: icmp_seq=0 ttl=63 time=7.871 ms
16 bytes from 10.45.1.51: icmp_seq=1 ttl=63 time=3.263 ms
16 bytes from 10.45.1.51: icmp_seq=2 ttl=63 time=3.184 ms
16 bytes from 10.45.1.51: icmp_seq=3 ttl=63 time=3.224 ms

--- 10.45.1.51 ping statistics ---
4 packets transmitted, 4 packets received, 0% loss
round-trip min/avg/max = 3/4/7 ms

3、在Switch上使用download 命令下载并安装Image：XCM8810.4 # download image 10.45.1.51 NG8800-12.4.4.10-1-7.xos VR-Default secondary

提示以下信息：

Do you want to install image after downloading? (y - yes, n - no, <cr> - cancel) Yes
（下载并安装？选择是）
Downloadin to MSM-A........................................................................................................
Downloading to MSM-B...................................................................................
This image will be used only after rebooting the switch!
Installing to primary partition!
Installing to MSM-B............................................................................................................................................................................................
Installing to MSM-A.............................................................................................................................................................................................

Image installed successfully
This image will be used only after rebooting the switch!
（只有重启之后，Image才会被激活！）

4、使用Use Image [Primary/Secondary] 来决定使用哪一个Image：

XCM8810.5 # use image ?
partition                            Image location
<partition>                            Partition
"primary"                            "secondary"

5、使用Reboot重启交换机并激活：

XCM8810.5 # reboot

注意：在第五步：Reboot 重启之前，交换机不会重启，不会断网。