Chosen Solution
Ouch! Sounds like you got the wrong CPU here. You need an Intel i7-4771 the i7-4790 won’t work as the EFI doesn’t know about it! (newer). The newer ‘Thin Series’ EFI’s seem to have the chip series coded in them as well as the TPD. So you can’t jump up to a newer version of the chip (assuming the chip will fit the socket correctly). Intel i7-4771 Processor SpecsIntel i7-4790 Processor Specs Sorry to say Apple offered an extended warranty on the hinge problem so you could have saved your self a bit of grief here ;-{ Apple Offering Refunds to Customers Who Paid for iMac Hinge Repairs as well as offered a free repair.
