Document how to force symbols:

https://www.raspberrypi.org/forums/viewtopic.php?t=228012

PKGBUILD

@@ -69,6 +69,8 @@ if [ -n "${LOCAL_PI_VER}" ]; then
         _xcompile_args="ARCH=arm CROSS_COMPILE=/opt/armv7-rpi2-linux-gnueabihf/bin/armv7-rpi2-linux-gnueabihf-"
     ;;
     3)
+        #symbols omitted by default wtf!
+        #DTC_FLAGS=\"-@ -H epapr\"
         echo "Compiling for the RPi 3 aarch64"
         _config_file="${startdir}/rpi3"
         _xcompile_args="ARCH=arm64 CROSS_COMPILE=/opt/x-tools/aarch64-rpi3-linux-gnu/bin/aarch64-rpi3-linux-gnu-"