Original post by: Matthias ,
The audio board from the 2009 A1225 is not compatible, one the flat cable connector is wider than on the 2008 and 2007 models. What worked for me was a downgrade of AppleHDA.kext to the El Capitan version (v. 274.12) instead of dosdude’s Legacy Audio Patch, sound is back to normal. Reg. bluetooth, that is fine too with 10.14.4 and dosdude’s patch tool 1.3.