diff --git a/default.nix b/default.nix
index f2bd688..c9d9107 100644
--- a/default.nix
+++ b/default.nix
@@ -65,8 +65,17 @@ let
       ls -la $src/ || true
       
       # Process docker-compose.yml first and create it in a temp location
+      # Replace .env paths AND volume mount paths to use writable directory
       if [ -f $src/docker-compose.yml ]; then
-        ${pkgs.gnused}/bin/sed 's|env_file:.*management-dashboard-web-app/\.env|env_file: /var/lib/usda-vision/.env|g; s|\./management-dashboard-web-app/\.env|/var/lib/usda-vision/.env|g' \
+        ${pkgs.gnused}/bin/sed \
+          -e 's|env_file:.*management-dashboard-web-app/\.env|env_file: /var/lib/usda-vision/.env|g' \
+          -e 's|\./management-dashboard-web-app/\.env|/var/lib/usda-vision/.env|g' \
+          -e 's|\./management-dashboard-web-app|/var/lib/usda-vision/management-dashboard-web-app|g' \
+          -e 's|\./media-api|/var/lib/usda-vision/media-api|g' \
+          -e 's|\./video-remote|/var/lib/usda-vision/video-remote|g' \
+          -e 's|\./scheduling-remote|/var/lib/usda-vision/scheduling-remote|g' \
+          -e 's|\./vision-system-remote|/var/lib/usda-vision/vision-system-remote|g' \
+          -e 's|\./camera-management-api|/var/lib/usda-vision/camera-management-api|g' \
           $src/docker-compose.yml > $TMPDIR/docker-compose.yml
       fi
       
@@ -223,6 +232,15 @@ in
       };
       
       preStart = ''
+        # Copy application code to writable directory if not already present or if source is newer
+        echo "Syncing application code to /var/lib/usda-vision..."
+        ${pkgs.rsync}/bin/rsync -av --delete \
+          --exclude='node_modules' \
+          --exclude='.env' \
+          --exclude='__pycache__' \
+          --exclude='.venv' \
+          ${usda-vision-app}/opt/usda-vision/ /var/lib/usda-vision/
+        
         # Ensure .env file exists with defaults if empty
         if [ ! -s /var/lib/usda-vision/.env ]; then
           if [ -f ${usda-vision-app}/opt/usda-vision/.env.example ]; then
@@ -236,18 +254,18 @@ in
       serviceConfig = {
         Type = "oneshot";
         RemainAfterExit = true;
-        WorkingDirectory = "${usda-vision-app}/opt/usda-vision";
+        WorkingDirectory = "/var/lib/usda-vision";
         User = "root";
         Group = "root";
         
-        # Start: pull latest images and start containers
-        ExecStart = "${pkgs.docker-compose}/bin/docker-compose -f ${usda-vision-app}/opt/usda-vision/docker-compose.yml up -d --build";
+        # Start: pull latest images and start containers from writable directory
+        ExecStart = "${pkgs.docker-compose}/bin/docker-compose -f /var/lib/usda-vision/docker-compose.yml up -d --build";
         
         # Stop: gracefully stop containers
-        ExecStop = "${pkgs.docker-compose}/bin/docker-compose -f ${usda-vision-app}/opt/usda-vision/docker-compose.yml down";
+        ExecStop = "${pkgs.docker-compose}/bin/docker-compose -f /var/lib/usda-vision/docker-compose.yml down";
         
         # Reload: restart containers
-        ExecReload = "${pkgs.bash}/bin/bash -c '${pkgs.docker-compose}/bin/docker-compose -f ${usda-vision-app}/opt/usda-vision/docker-compose.yml down && ${pkgs.docker-compose}/bin/docker-compose -f ${usda-vision-app}/opt/usda-vision/docker-compose.yml up -d --build'";
+        ExecReload = "${pkgs.bash}/bin/bash -c '${pkgs.docker-compose}/bin/docker-compose -f /var/lib/usda-vision/docker-compose.yml down && ${pkgs.docker-compose}/bin/docker-compose -f /var/lib/usda-vision/docker-compose.yml up -d --build'";
         
         TimeoutStartSec = 300;
         TimeoutStopSec = 120;