As an example, I will use D-Link DAP-1155 with firmware 1.0.0.
I will describe the steps in steps:
1) Download the new firmware from the official website:
http://www.dlink.ru/ru/products/2/1473_d.html
At the time of writing, I was downloading version 2.0.10 for revision B1.
2) Let’s open the router settings by typing in the browser the address 192.168.0.50 and enter the standard login – admin, password – admin.
3) In the interface that opens, click on the “Advanced Settings” button and in the “System” block, click on the arrows “>>”, where then we select “Software Update”. In the window that opens, click “Browse” and select the previously downloaded firmware file, then click “Update” to start the update process.
Wait for the update to complete, usually 2-5 minutes.
At the end, the device will reboot.
Done. After the firmware update, the settings remained unchanged.
I updated the firmware remotely through the WAN port.