The D-Link DSL-124 is a wireless N300 ADSL2+ modem router, commonly found in home and small office environments relying on DSL (copper line) internet.
Most DSL-124 firmware versions allow downgrading via the same web UI.
If downgrade is blocked: D-link Dsl-124 Firmware
Security: Supports WPA/WPA2 and WEP encryption, alongside a Stateful Packet Inspection (SPI) firewall and Quality of Service (QoS). Firmware Management Title: D-Link DSL-124 Firmware: The Critical Need to
Before starting, you must ensure you have the correct file for your specific hardware version. Wireless N 300 ADSL2+ 4-Port Router DSL-124 - D-Link D-link Dsl-124 Firmware