rpi-netboot: fix kernel

modules/audio-server.nix

@@ -6,7 +6,8 @@
   };
 
   config = lib.mkIf config.c3d2.audioServer.enable {
-    boot.kernelPackages = pkgs.linuxPackages-rt_latest;
+    # higher than mkDefault but lower than no priority to allow easy overwriting in rpi-netboot
+    boot.kernelPackages = lib.mkOverride 900 pkgs.linuxPackages-rt_latest;
 
     environment.systemPackages = with pkgs; [
       mpd

modules/rpi-netboot.nix

@@ -12,6 +12,9 @@
         enable_uart=0
       '';
     };
+    # repeat https://github.com/NixOS/nixos-hardware/blob/master/raspberry-pi/4/default.nix#L20
+    # to overwrite audio module
+    kernelPackages = pkgs.linuxKernel.packages.linux_rpi4;
     kernelParams = [
       "verbose" "shell_on_fail"
       "elevator=deadline"