I have just installed the decoder and cartridges on my dedicated color P800 (my Piezography one has been working great for two years now).
I get cartridge not installed correcly error for C, VM, LC, VLM, and Y. MK is greyed out. PK, LK and LLK are ok.
I tried the OEM cartridges and get the same error… I have not made any firmware updates.
Included photos of the maessage and decoder…