新到一个1815i 无线接入点，使用过的， 需要重置并刷ME系统。
断电、断poe， 插上 console 线， 用工具先按住机壳的mode 按钮，再插poe 网线
Button is pressed. Configuration reset activated..
Keep the button pressed for > 20 seconds for full reset
Wait for the button to be released ....
Button pressed for 24 seconds
Setting env for full reset..
Writing to Nand...
有一个20秒以上的提示信息后，下面的pressed 会计数， 超过20 即可， 不能超过60， 不然超过60 不会修改任何配置。
Using the Mode Button
Using the Mode button (see Figure 6) you can:
To use the mode button, press, and keep pressed, the mode button on the access point during the boot cycle. Wait until the status LED changes to Amber. During this, the AP console shows a seconds counter, counting the number of seconds the mode button is pressed. Then:
This resets all configuration settings to factory defaults, including passwords, encryption keys, the IP address, and the SSID. However, the regulatory domain provisioning is not reset.
To clear the AP internal storage, including all configuration files, keep the mode button pressed for more than 20 seconds, but less than 60 seconds.
The AP status LED changes from Amber to Red, and all the files in the AP storage directory are cleared.
If you keep the mode button pressed for more than 60 seconds, the mode button is assumed faulty and no changes are made.