diff --git a/update-Nitrov3.sh b/update-Nitrov3.sh
index daac557..bf6a765 100755
--- a/update-Nitrov3.sh
+++ b/update-Nitrov3.sh
@@ -18,6 +18,11 @@ if [ -z "${_UNBUFFERED:-}" ] && command -v unbuffer &> /dev/null; then
 fi
 exec 2>&1
 
+# Single-instance lock via flock
+LOCKFILE="/tmp/$(basename "$0").lock"
+exec 200>"$LOCKFILE"
+flock -n 200 || { echo "=== ❌ Another instance already running, exiting ==="; exit 1; }
+
 # Trap for clean error messages
 trap 'echo "=== ❌ ERROR: Update failed at line $LINENO (command: $BASH_COMMAND) ===" >&2; exit 1' ERR
 
@@ -46,10 +51,10 @@ NITRO_GAMEDATA_URL="${NITRO_GAMEDATA_URL:-https://epicnabbo.nl/gamedata}"
 NITRO_ASSET_URL="${NITRO_ASSET_URL:-https://epicnabbo.nl/gamedata/bundled}"
 NITRO_FURNI_ASSET_ICON_URL="${NITRO_FURNI_ASSET_ICON_URL:-https://epicnabbo.nl/gamedata/icons/%libname%%param%_icon.png}"
 
-# Build MySQL/MariaDB credentials argument
+# Build MySQL/MariaDB credentials argument (password via MYSQL_PWD — not visible in ps)
 MYSQL_CRED="-h $DB_HOST -P $DB_PORT -u $DB_USER"
 if [ -n "$DB_PASS" ]; then
-    MYSQL_CRED="$MYSQL_CRED -p$DB_PASS"
+    export MYSQL_PWD="$DB_PASS"
 fi
 # ---------------------
 
@@ -68,7 +73,10 @@ echo "=== Starting EPIC WEB CONTROL Update ==="
 # ----------------------------------------
 echo "--> Updating Emulator..."
 cd "$EMULATOR_DIR/Emulator/"
-git stash --include-untracked || true && git checkout main && git pull
+git stash --include-untracked || true
+OLD_HEAD=$(git rev-parse HEAD)
+git checkout main
+git pull
 
 # --- Automatic Safe Database Backup ---
 echo "--> Creating automatic database backup before update..."
@@ -86,23 +94,22 @@ else
     echo "--> SQL directory not found, skipping SQL import."
 fi
 
-echo "--> Building Emulator with Maven..."
-mvn package
+if [ "$(git rev-parse HEAD)" != "$OLD_HEAD" ]; then
+    echo "--> New commits detected, building emulator..."
+    mvn package
 
-# Automatically detect the newly built .jar file
-JAR_PATTERN="target/Habbo-*-jar-with-dependencies.jar"
-JAR_FILE=$(basename "$(ls -t $JAR_PATTERN 2>/dev/null | head -n 1)")
+    JAR_FILE=$(find target -maxdepth 1 -name 'Habbo-*-jar-with-dependencies.jar' -printf '%T@ %p\n' 2>/dev/null | sort -rn | sed -n '1s/^[0-9.]* //p' | xargs basename)
 
-if [ -z "$JAR_FILE" ]; then
-    echo "=== ❌ No jar file found with pattern: $JAR_PATTERN ==="
-    exit 1
-fi
+    if [ -z "$JAR_FILE" ]; then
+        echo "=== ❌ No jar file found with pattern: target/Habbo-*-jar-with-dependencies.jar ==="
+        exit 1
+    fi
 
-echo "--> Found jar file: $JAR_FILE"
-echo "--> Updating emulator launch file..."
-cd target/
+    echo "--> Found jar file: $JAR_FILE"
+    echo "--> Updating emulator launch file..."
+    cd target/
 
-cat << EOF > emulator
+    cat << EOF > emulator
 #!/bin/sh
 file_name_emulator=emulator.log
 current_time=\$(date "+%H%M_%d-%m-%Y")
@@ -110,7 +117,10 @@ file_name=\$file_name_emulator.\$current_time
 mv /var/log/emu/emulator.log /var/log/emu/\$file_name
 java -Dfile.encoding=UTF8 -Xmx2G -jar $JAR_FILE
 EOF
-chmod +x emulator
+    chmod +x emulator
+else
+    echo "--> Emulator already up to date, skipping build."
+fi
 
 
 # ----------------------------------------
@@ -119,11 +129,17 @@ chmod +x emulator
 echo "--> Updating Nitro_Render_V3..."
 cd "$NITRO_RENDERER/"
 
-git stash --include-untracked || true && git checkout main && git pull
+git stash --include-untracked || true
+OLD_HEAD=$(git rev-parse HEAD)
+git checkout main
+git pull
 
-echo "--> Running yarn install for Nitro_Render_V3..."
-clean_node_modules
-yarn install
+if [ "$(git rev-parse HEAD)" != "$OLD_HEAD" ]; then
+    echo "--> New commits detected, running yarn install for Nitro_Render_V3..."
+    yarn install --frozen-lockfile || { echo "--> Retrying with clean node_modules..."; clean_node_modules && yarn install; }
+else
+    echo "--> Nitro_Render_V3 already up to date, skipping."
+fi
 
 
 # ----------------------------------------
@@ -132,14 +148,18 @@ yarn install
 echo "--> Updating Nitro-V3..."
 cd "$NITRO_CLIENT"
 
-git stash --include-untracked || true && git checkout main && git pull
+git stash --include-untracked || true
+OLD_HEAD=$(git rev-parse HEAD)
+git checkout main
+git pull
 
-echo "--> Running yarn install for Nitro-V3..."
-clean_node_modules
-yarn install
-
-echo "--> Building Nitro-V3 with Vite 8 / Yarn..."
-yarn build
+if [ "$(git rev-parse HEAD)" != "$OLD_HEAD" ]; then
+    echo "--> New commits detected, building Nitro-V3..."
+    yarn install --frozen-lockfile || { echo "--> Retrying with clean node_modules..."; clean_node_modules && yarn install; }
+    yarn build
+else
+    echo "--> Nitro-V3 already up to date, skipping build."
+fi
 
 echo "--> Ensuring custom-themes/index.json exists..."
 mkdir -p "$NITRO_CLIENT/dist/custom-themes"
@@ -158,25 +178,16 @@ echo "--> Synchronizing configurations..."
 mkdir -p "$GAMEDATA_CONF_DIR"
 
 MERGE_SCRIPT="$(dirname "$0")/scripts/merge-config.cjs"
+NITRO_DIST_CONFIG_DIR="$NITRO_CLIENT/dist/configuration"
 
-# Phase 1: Merge .example with live configs in the same public directory
-# so the Nitro client always has 100% complete configs
-echo "--> Merging .example files with live configs in $NITRO_SRC_DIR..."
-for example_file in "$NITRO_SRC_DIR"/*.example; do
-    [ -f "$example_file" ] || continue
-    base=$(basename "$example_file")
-    target_name="${base%.example}"
-    case "$target_name" in
-        *.*) ;;  # already has extension (e.g., .json, .json5)
-        *) target_name="$target_name.json" ;;  # no extension -> add .json
-    esac
-    live_path="$NITRO_SRC_DIR/$target_name"
-    echo "--> Processing $base -> $target_name (live)..."
-    node "$MERGE_SCRIPT" "$example_file" "$live_path"
+# Temporarily make config dirs writable if owned by www-data (restored in section 6)
+for dir in "$NITRO_SRC_DIR" "$GAMEDATA_CONF_DIR"; do
+    if [ -d "$dir" ] && [ ! -w "$dir" ] && command -v sudo &> /dev/null; then
+        sudo chown -R "$(whoami)":"$(whoami)" "$dir"
+        echo "--> [OK] Made $dir writable (will restore to www-data later)"
+    fi
 done
 
-# Phase 2: Then merge the same to Gamedata/config for the website
-echo "--> Merging Nitro config examples into Gamedata/config..."
 for example_file in "$NITRO_SRC_DIR"/*.example; do
     [ -f "$example_file" ] || continue
     base=$(basename "$example_file")
@@ -185,29 +196,21 @@ for example_file in "$NITRO_SRC_DIR"/*.example; do
         *.*) ;;
         *) target_name="$target_name.json" ;;
     esac
-    target_path="$GAMEDATA_CONF_DIR/$target_name"
-    echo "--> Processing $base -> $target_name..."
-    node "$MERGE_SCRIPT" "$example_file" "$target_path"
-done
 
-# Phase 3: Sync merged configs to dist/configuration for the live client
-NITRO_DIST_CONFIG_DIR="$NITRO_CLIENT/dist/configuration"
-if [ -d "$NITRO_DIST_CONFIG_DIR" ]; then
-    echo "--> Syncing merged configs to dist/configuration/..."
-    for example_file in "$NITRO_SRC_DIR"/*.example; do
-        [ -f "$example_file" ] || continue
-        base=$(basename "$example_file")
-        target_name="${base%.example}"
-        case "$target_name" in
-            *.*) ;;
-            *) target_name="$target_name.json" ;;
-        esac
-        if [ -f "$NITRO_SRC_DIR/$target_name" ]; then
-            cp "$NITRO_SRC_DIR/$target_name" "$NITRO_DIST_CONFIG_DIR/$target_name"
-            echo "--> [OK] Synced $target_name to dist/configuration/"
-        fi
-    done
-fi
+    # Phase 1: Merge to live config in Nitro public dir
+    echo "--> Merging $base -> $target_name (live)..."
+    node "$MERGE_SCRIPT" "$example_file" "$NITRO_SRC_DIR/$target_name"
+
+    # Phase 2: Merge to Gamedata/config for website
+    echo "--> Merging $base -> $target_name (gamedata)..."
+    node "$MERGE_SCRIPT" "$example_file" "$GAMEDATA_CONF_DIR/$target_name"
+
+    # Phase 3: Copy merged config to dist/configuration for live client
+    if [ -d "$NITRO_DIST_CONFIG_DIR" ]; then
+        cp "$NITRO_SRC_DIR/$target_name" "$NITRO_DIST_CONFIG_DIR/$target_name"
+        echo "--> [OK] Synced $target_name to dist/configuration/"
+    fi
+done
 
 # Phase 4: Restore critical icon URLs in renderer-config and ui-config
 # (prevents git pull from overwriting URLs with example values)
@@ -265,7 +268,7 @@ echo "--> Starting automated cleanup..."
 
 # 1. Remove emulator logs older than 14 days
 echo "--> Removing emulator logs older than 14 days..."
-find "$EMULATOR_DIR/" -name "*.log" -mtime +14 -exec rm -f {} \; 2>/dev/null || true
+find "$EMULATOR_DIR" -name "*.log" -mtime +14 -exec rm -f {} \; 2>/dev/null || true
 
 # 2. Keep max 5 newest database backups, delete older ones
 echo "--> Managing update backups (keeping max 5)..."