If you tell me your exact (from the router label), I can help you narrow down the correct firmware name.

The D-Link DSL-2750U Wireless N300 ADSL2+ Modem Router is a legendary workhorse in the world of home networking. Known for its reliability and versatile features, it remains a staple for many households. However, to keep your connection secure and performing at its peak, staying updated with the latest firmware is non-negotiable.

Never update firmware over a wireless connection; use an Ethernet cable to prevent connection drops that could permanently damage the router. Wireless N ADSL2+ WI-FI Router DSL-2750U - D-Link

Ensure your router and computer will not lose power during the 5-minute update window.

Always avoid third-party websites offering "hot" or "unlocked" firmware downloads. These files often contain malware, spyware, or unstable modifications that can ruin your device. Always download directly from official D-Link regional servers. Step-by-Step Download Instructions

Follow these steps exactly to avoid interrupting the installation process. Step 1: Prepare Your Connection