I guess that everyone has given up on this now (especially HP?) but if anyone has a solution to printing A3 borderless or indeed A4 borderless on Plain paper I'd be very grateful to hear.
Mercifully I've managed to get through the last few months without needing borderless, but now I do desperately and it seems terrible that this otherwise OK printer can not do what HP claimed it could do when I bought it.
I did for a long time this: "Setting the printer to other paper, then it was possible to print A3 borderless". But at the end the printer started making paperjam 50% of the print, then 80%, so now I only use the HP printer for plain A4 print, and bought another printer for my borderless print.
As far as I remember HP ended telling me that this printer is not made to print A3 borderless on normal paper, and it was not something that could be solved by and update (perhaps becausce they have testet and found out that in time the printer would start paperjamming)
I gave up, but if someone find a solution it would be nice to know. But unfortunaly I don't think it would be solved 😞