I have successfully installed macOS Big Sur on my dell optiplex 3060 every thing work's except the mic it has ALC255 codec the internal speakers and front combo jack earphones speaker works but the mic of earphone does not work the back LINE IN port does nothing. I am using layout id 11 I have also installed the combo jack app but no luck, there is no pop up screen when plugging in the earphones.
My EFI.zip