Workforce Pro 7840: Tried all this and it didn't work (updated recovery I think) but I did buy these https://www.amazon.com/dp/B0D127FXCM?ref... (812XL Ink Cartridges High Yield Remanufactured Replacement for Epson 812 XL T812XL 812 to use with WF-7820 WF-7840 WF-7310 EC-C7000 P) for 42.99 swapped the chips out and worked perfectly AND I don't need to change them as they are not one use!