Link to profile in activation script instead of nix-on-droid

modules/build/activation.nix

@@ -108,6 +108,13 @@ in
         internal = true;
         description = "Package containing /etc files.";
       };
+
+      profileDirectory = mkOption {
+        type = types.path;
+        readOnly = true;
+        internal = true;
+        description = "Path to nix-on-droid profile.";
+      };
     };
 
   };
@@ -117,7 +124,13 @@ in
 
   config = {
 
-    build.activationPackage =
+    build = {
+      activationAfter.linkProfile = ''
+        generationDir="$(dirname "$(realpath $0)")"
+        $DRY_RUN_CMD nix-env --profile "${cfg.profileDirectory}" --set "$generationDir"
+      '';
+
+      activationPackage =
         pkgs.runCommand
           "nix-on-droid-generation"
           {
@@ -139,6 +152,9 @@ in
             ln --symbolic ${config.environment.usrBinEnv} $out/filesystem/usr/bin/env
           '';
 
+      profileDirectory = "/nix/var/nix/profiles/nix-on-droid";
+    };
+
   };
 
 }

nix-on-droid/nix-on-droid.sh

@@ -34,7 +34,9 @@ function doHelp() {
 }
 
 function doSwitch() {
-    local profileDirectory="/nix/var/nix/profiles/nix-on-droid"
+    if [[ -v VERBOSE ]]; then
+        PASSTHROUGH_OPTS+=(--show-trace)
+    fi
 
     echo "Building activation package..."
     nix build \
@@ -43,15 +45,13 @@ function doSwitch() {
         ${PASSTHROUGH_OPTS[*]} \
         activationPackage
 
-    echo "Save profile activation package..."
+    echo "Run activation script..."
     generationDir="$(nix path-info \
         --file "<nix-on-droid/modules>" \
         ${PASSTHROUGH_OPTS[*]} \
         activationPackage \
     )"
-    nix-env --profile "${profileDirectory}" --set "${generationDir}"
 
-    echo "Run activation script..."
     "${generationDir}/activate"
 }