HP C4480 Incompatible Print Ink Cartridge Fix

There are 2 ways to fix this, and either one is super easy. If just leaving the cartridges out for a few minutes and them putting them back in doesn't work you can always reset the checksum by doing the following... 1: Press 'X' and the power button at the same time. It will display «Enter Special Key Combo» 2: In Order Press Blue, Green and then Grey 3: Press 'OK' 4: Press the blue button until you see «checksum for relock data input» 5: Press 'OK' twice (the first time will display a number) 6: Press X three times. 7: Presto! Start printing with your «incompatible ink»