To update the firmware for version J1, follow these critical steps: How to update your D-link router (DSL 2750) - step by step
: Versions prior to vME1.16 (on related revisions) have been identified with vulnerabilities like unauthorized configuration access. Always use the most recent version available for your specific region and hardware or configuring specific settings like 3G failover Wireless N ADSL2+ WI-FI Router DSL-2750U - D-Link d-link dsl-2750u h w ver j1 firmware
Custom firmware voids your warranty and requires technical knowledge. The process is more complex than a standard update. To update the firmware for version J1, follow