If you own an HP OfficeJet Pro 8620 and you’ve recently noticed that your third-party ink cartridges no longer work, your printer refuses to scan, or you are seeing cryptic “Cartridge Problem” errors, you are not alone. You have been hit by HP’s infamous Dynamic Security feature.
: Experienced users on Reddit suggest that while the official .exe installer acts as a "gatekeeper" and blocks downgrades, you can bypass this by extracting the .FUL or .RFU binary file and sending it directly to the printer via a network command (like LPR or binary copy). hp officejet pro 8620 firmware downgrade hot
Connect the printer directly to your computer using a USB A-to-B printer cable. If you own an HP OfficeJet Pro 8620