I have worked with this issue for 5 days and was not able to resolve this issue working with HP on the phone. When you update the firmware with the accessories attached it does something to them. I have read some of the replies that said they had some success and some 100 percent.
My success was none exept after i replace the complete tray. I opened the unit and found that it has a PCA Board with Transistor, resistors, caps, coils and diods. Get part number RM1-5085 and i think it should work.
It seemd to me that while updating the 4015 Models, it possibly spikes that board as you wil notice that there is no chip or Rom. I found a link i am not affiliated with but just take a look and find one anywhere on the net. http://www.laserxperts.com/SingleProd.asp?ProdID=2195&LineID=54
Rich