Downgrading the firmware on an HP OfficeJet Pro 8620 Go to product viewer dialog for this item.
Your printer may show errors even though the cartridges have ink. The only solution for many is to downgrade to an older firmware version that existed before the latest security patch. hp officejet pro 8620 firmware downgrade
Before attempting a downgrade, you must adjust the printer's internal settings to allow the installation of older software. Downgrading the firmware on an HP OfficeJet Pro