I purchased a flip key from eBay with electronics and virgin 4D63 chip. It was advertised as being compatible with mk2 Focus 04-10, I own a 2006 mk2 so all should have been good

Today I took it to three different shops and each said the chip did not match the one in my current key and was from a later model. The last guy offered to swap out the blade/chip so it would work with mine, price was 80 euro. I went ahead because I was just wasting too much time driving around trying to sort it out.

From what I have read once the key is cut they then need to connect to the ecu to program the chip but this guy was able to do it in the shop and then just sort out the electronics side of it so it would open the door.

What made mine so different? I would like to message the eBay seller and let them know that the chip was not compatible with my mk2, was there different chips used between 04-10?

Flip keys use a flat 'carbon' chip but I guarantee they are compatible with the mk2.

I had one done for my old mk2 and for the duration of ownership it was the only key I used daily and never had any problems.

I suspect that they swapped the chips over as the carbon ones can't be cloned whereas the glass ones can.