diff --git a/MMDVMHost/module.nix b/MMDVMHost/module.nix
index 9bde484..0e72c94 100644
--- a/MMDVMHost/module.nix
+++ b/MMDVMHost/module.nix
@@ -10,17 +10,17 @@ in
 
   options.services.mmdvm_host = {
     enable = mkEnableOption "MMDVMHost service";
-    
+
     host_package = mkOption {
-      default = mmdvm_host.x86_64-linux.default;
+      default = mmdvm_host;
       type = types.package;
     };
 
     firmware_package = mkOption {
-      default = mmdvm_firmware.x86_64-linux.default;
+      default = mmdvm_firmware;
       type = types.package;
     };
-    
+
     user = mkOption {
       type = types.str;
       default = "afg";
@@ -32,7 +32,7 @@ in
     };
 
     config-file = mkOption {
-      type = types.str;
+      type = types.path;
     };
 
     usb-tty = mkOption {
@@ -44,13 +44,15 @@ in
 
 
   config = mkIf cfg.enable {
-    # List packages installed in system profile. To search, run:
-    # $ nix search wget
     environment.systemPackages = [
       pkgs.stm32flash
       cfg.host_package
     ];
 
+    systemd.tmpfiles.rules = [
+      "d '/var/lib/mmdvm' 0750 ${cfg.user} ${cfg.group} - -"
+    ];
+
     systemd.services.mmdvm_host = {
       wantedBy = [ "multi-user.target" ];
       wants = [ "network.target" ];
@@ -66,15 +68,14 @@ in
       };
       script = ''
         if [ ! -e /var/lib/mmdvm/firmware-version ]; then
-          mkdir -p /var/lib/mmdvm
           touch /var/lib/mmdvm/firmware-version
         fi
         if [ "${cfg.firmware_package}" != "$(cat /var/lib/mmdvm/firmware-version)" ]; then
           ${pkgs.stm32flash}/bin/stm32flash -w ${cfg.firmware_package}/firmware/mmdvm_f4.bin -i ',-dtr,-rts,dtr,,:-dtr,rts,dtr' ${cfg.usb-tty}
-          echo "{cfg.firmware_package}" > /var/lib/mmdvm/firmware-version
+          echo "${cfg.firmware_package}" > /var/lib/mmdvm/firmware-version
         fi
         
-        exec ${cfg.package}/bin/MMDVMHost ${cfg.config-file}
+        exec ${cfg.host_package}/bin/MMDVMHost ${cfg.config-file}
       '';
     };
   };