Attach a computer to a physical LAN port via an Ethernet cable.
Official OpenWrt 19.07+ dropped support for the HG255s. You will need to find community-maintained images from archives or dedicated forums. hg255s firmware
Based on the typical intent behind searching for "HG255s firmware," the following piece is a practical guide focused on the device's legacy status, the custom firmware options available, and the technical process of flashing the router. Attach a computer to a physical LAN port