Check your original version. If your printer has a version ending in NU (Not Upgradable), you must use a specifically modified fix that bypasses signature verification.

This process voids the manufacturer's warranty.

Because firmware fixes are customized to your specific printer Serial Number or CRUM number, generic public download links rarely work and can damage your machine.

A firmware reset rolls back the printer to an older version (e.g., V3.00.01.07 or earlier) that ignores toner counters and allows any cartridge to work.