本内容主要介绍关于cisco IOS平台的单台设备升级步骤，希望帮助到大家：
1. 准备软件版本
在思科官方网站（官网传送门）下载你需要的系统版本文件。
2. 将版本文件上传到设备（有两种方式上传到设备）：
1）用FTP/TFTP上传
Switch#copy tftp: flash:
Address or name of remote host [x.x.x.x]?
Source filename [c3750e-universalk9-mz.152-4.E10.bin]? c3750e-universalk9-mz.152-4.E10.bin
Destination filename [c3750e-universalk9-mz.152-4.E10.bin]?
Accessing tftp://x.x.x.x/c3750e-universalk9-mz.152-4.E10.bin...
Loading c3750e-universalk9-mz.152-4.E10.bin from x.x.x.x (via Vlan1)
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!--- Output is truncated.
[OK - 8172194 bytes]
8172194 bytes copied in 203.718 secs (40115 bytes/sec)
2）用设备USB接口上传
Switch#copy usbflash0:c3750e-universalk9-mz.152-4.E10.bin flash:
3. 检查当前设备的启动路径
Switch#show boot
BOOT path-list : flash:c3750e-universalk9-mz.150-2.SE10a.bin
Config file: flash:/config.text
Private Config file: flash:/private-config.text
4. 使用boot system命令设置用新的镜像启动设备：
Switch(config)#no boot system
Switch(config)#boot system flash:c3750e-universalk9-mz.152-4.E10.bin
5. 验证引导变量:
Switch#show boot
BOOT path-list: flash:c3750e-universalk9-mz.152-4.E10.bin
Config file: flash:/config.text
Private Config file: flash:/private-config.text
6. 重启设备
Switch#write
Switch#reload
7. 检查版本是否升级成功：
Switch#show version
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
1 30 WS-C3750X-24P 15.2.4E10 C3750E-UNIVERSALK9-M
