HP SmartTank 551 Firmware Downgrade?

Not sure where to put this on here. I have a SmartTank 551 that has worked flawlessly since I bought it and has printed over 10,000 pages in its lifetime. The thing is a beast. Until this spring when an update was pushed and now it keeps randomly printing out a diagnostic page and keeps on trying until my feed tray is empty. I don’t think this is something HP did for “forced replacement” or anything like that because I have not seen a mention of it online.

I have done a few factory resets and even left it offline thinking it was another device triggering it. No dice. HP support it useless and just wants me to do a factory reset on my printer and computer. Morons. The only thing I can think of is the printer had a malfunction during the update and the firmware is corrupted. I tried to do a firmware update using HP’s software but it will not let me since the printer is already on the newest firmware. I would just retire this thing and get a Brother but they do not have a tank printer like the Smart Tanks or Epson’s Eco-tanks.

Any ideas on this? There has to be someone here that knows how to hack the update software or the printer itself.

I found this site https://www.memorysieve.co.uk/2015/10/update-firmware-hp-officejet-6500a-plus.html?ref=nullsec.us and tried to send the file but it didn’t seem to do anything.

BTW, is there a similar command in Linux to the “copy -b” the site refers to?