"To upgrade the firmware on your DSL-2750U HW C1, follow these steps:
Do not download "custom" or "unlocked" firmware from random file-hosting sites. Stick to the official D-Link support portal or trusted repositories like TPLD (Telecom-People List Database) .
The C1 version has decent Wi-Fi capabilities, but the default settings are often optimized for compatibility rather than speed.
Annex setting changed. Fix:
PMF (Protected Management Frames) incompatibility. Fix: