usually you would download the code then you would open the xcode.proj file then compile but you can just download the built file here https://github.com/Grid-H/OS-X-BrcmPatchRAM/releases
kext injection is also needed if you are booting from an installer or .DMG image as the cache is predefined and compressed within the installer that is normally not accessible.
in the case of an installer the folder Efi/Clover/Kexts/Other should be used.
correct your smbios. it is coded with 3 machine identifiers.
MacBook8,1
MacBookAir7,1
MacBookPro12,1
pick an smbios that will work for your machine and that is supported by 10.14.4
what herve said. the kext is Dr.Hurts hard work not mine.
i had no involvement in it.
i did not have anything to do with writing the code for the kext. i just compiled Dr.Hurts last code he left us with so that we could try it.
make sure your BT shows up on your USB bus first. if it is not there then you have to resolve that issue first if not no driver will ever load if it does not see the device