最近我将EdgeRouter-X的固件从1.10.9升级到2.01，在使用过程中，发现新固件不太稳定，于是为了谨慎起见，我决定将路由器的固件降级回v1.10.9。
查询了官方网站，发现恢复路由器上的旧版本固件非常简单，因为无论何时执行固件升级，EdgeOS都会将当前固件设置为辅助固件，而不会去删除旧固件，这为我们恢复旧固件提供了简便的方法。下面我们进入CLI界面来进行恢复。
第一步：运行“ show system image ”查看路由器上当前的固件。
Admin@router:~$ show system image
The system currently has the following image(s) installed:
v2.0.1.5174691.190312.1617 (running image) (default boot)
v1.10.9.5166958.190213.1952-1第二步：运行’ set system image default-boot ‘切换要引导的固件。
Admin@router:~$ set system image default-boot
The system currently has the following image(s) installed:
v2.0.1.5174691.190312.1617 (running image) (default boot)
v1.10.9.5166958.190213.1952-1
Are you sure you want to switch images? (Yes/No) [Yes]: Yes第三步：回答“yes”，将进行固件切换，输出信息如下：
Moving images...
Done
Switched from
Version: v2.0.1.5174691.190312.1617
to
Version: v1.10.9.5166958.190213.1952-1第四步：再次运行“ show system image ”来验证固件是否已成功切换
Admin@router:~$ show system image
The system currently has the following image(s) installed:
v1.10.9.5166958.190213.1952-1 (default boot)
v2.0.1.5174691.190312.1617 (running image)
A reboot is needed to boot default image第五步：运行’reboot’重启来进行固件切换。
Admin@router:~$ reboot
