Chosen Solution

My ear speaker flex is damaged on my iPhones x. If I buy another ear speaker flex with all sensors but put the original flood illuminator on it will Face ID work?

Yes actually you need to insert the old one because that one is compatibie with one like finger print in iPhone only like one in one phone . Absoulatly yes you can.

IS there a guide on this? My iPhone does not boot up with my earpiece flex connected to the logicboard, but it does boot up without it connected, or with a replacement part connected.