Do not attempt this over Wi-Fi. A physical connection prevents data corruption.
If you want, I can:
On the printer control panel, go to > Printer Maintenance . Select Update the Printer . Go to Printer Update Options and select Do Not Check . Select No when asked if you want to turn on updates. 2. Enter Service Mode (Optional but Recommended) hp officejet pro 8620 firmware downgrade
A critical hardware risk exists when downgrading. If a user installed a third-party cartridge while on new firmware, the printer may have written data to the cartridge chip identifying it as "used in a locked printer." Downgrading the printer firmware might not unlock these cartridges, as the lock status is stored on the cartridge's own IC. The printer may continue to reject them, rendering the downgrade futile for that specific set of consumables. Do not attempt this over Wi-Fi
Most 8620s accept direct downgrades, but if you get a "Downgrade not allowed" error: Select Update the Printer
HP’s "Dynamic Security" feature is designed to ensure that only new, genuine HP cartridges work in their printers. While HP claims this protects print quality and security, critics argue it is a tactic to lock customers into expensive first-party ink.