A printhead controller is provided for supplying print data to a printhead having first and second rows of inkjet nozzles configured to print ink of a similar color. The controller is configured to supply the print data to the printhead such that, in the event a nozzle in the first row is faulty, a corresponding nozzle in the second row prints at a position on print media at or adjacent a position where the faulty nozzle would otherwise have printed.