diff --git a/setup.sh b/setup.sh
index 8c74e51..0729850 100644
--- a/setup.sh
+++ b/setup.sh
@@ -21,14 +21,12 @@ sudo apt update && sudo apt upgrade -y
 # ---------------------------------------------------------
 echo "Step 2: Installing required tools..."
 sudo apt install -y git curl python3 python3-pip build-essential cmake \
-  python3-serial
+  python3-serial libusb-dev
 
 # ---------------------------------------------------------
 # Step 2.5: Install teensy-loader-cli from source
 # ---------------------------------------------------------
 echo "Installing teensy-loader-cli manually from source..."
-sudo apt install -y libusb-dev
-
 cd "$HOME"
 if [ ! -d teensy_loader_cli ]; then
   git clone https://github.com/PaulStoffregen/teensy_loader_cli.git
@@ -40,6 +38,17 @@ sudo cp teensy_loader_cli /usr/local/bin/teensy-loader-cli
 echo "Verifying teensy-loader-cli..."
 teensy-loader-cli --version || echo "⚠️ teensy-loader-cli failed to install properly"
 
+# ---------------------------------------------------------
+# Step 2.6: Install udev rules for Teensy
+# ---------------------------------------------------------
+echo "Installing udev rules for Teensy access..."
+cd "$HOME"
+wget -O 49-teensy.rules https://www.pjrc.com/teensy/49-teensy.rules
+sudo cp 49-teensy.rules /etc/udev/rules.d/
+sudo udevadm control --reload-rules
+sudo udevadm trigger
+echo "✅ Teensy udev rules installed. Reboot required to take effect."
+
 # ---------------------------------------------------------
 # Step 3: Install Arduino CLI manually (latest version)
 # ---------------------------------------------------------
@@ -69,28 +78,64 @@ else
 fi
 
 # ---------------------------------------------------------
-# Step 5: Download Teensy firmware and flash if available
+# Step 5: Download Teensy firmware
 # ---------------------------------------------------------
 echo "Step 5: Downloading Teensy firmware..."
 cd "$HOME"
 wget -O ltc_audiohat_lock.ino.hex https://raw.githubusercontent.com/cjfranko/NTP-Timeturner/master/firmware/ltc_audiohat_lock.ino.hex
 
-echo "Checking for connected Teensy 4.0..."
+# ---------------------------------------------------------
+# Step 6: Create flash script and one-time service
+# ---------------------------------------------------------
+echo "Step 6: Creating one-time flash script and service..."
+cat << 'EOF' > "$HOME/flash_teensy_once.sh"
+#!/bin/bash
+echo "🔧 Running one-time Teensy flash..."
 if ls /dev/ttyACM* 1> /dev/null 2>&1; then
   echo "✅ Teensy detected. Flashing firmware..."
-  teensy-loader-cli --mcu=TEENSY40 -w -v ltc_audiohat_lock.ino.hex
-  echo "✅ Firmware uploaded successfully."
+  /usr/local/bin/teensy-loader-cli --mcu=TEENSY40 -w -v "$HOME/ltc_audiohat_lock.ino.hex"
+  echo "✅ Firmware upload complete."
 else
-  echo "⚠️ No Teensy detected on /dev/ttyACM* — firmware not flashed."
+  echo "⚠️ No Teensy detected on /dev/ttyACM* — skipping flash."
 fi
 
+# Clean up: remove script and disable this service
+rm -- "$HOME/flash_teensy_once.sh"
+systemctl --user disable flash-teensy.service
+rm -- "$HOME/.config/systemd/user/flash-teensy.service"
+EOF
+
+chmod +x "$HOME/flash_teensy_once.sh"
+
+mkdir -p "$HOME/.config/systemd/user"
+cat << EOF > "$HOME/.config/systemd/user/flash-teensy.service"
+[Unit]
+Description=One-time Teensy Flash
+After=default.target
+
+[Service]
+Type=oneshot
+ExecStart=$HOME/flash_teensy_once.sh
+RemainAfterExit=true
+
+[Install]
+WantedBy=default.target
+EOF
+
+systemctl --user daemon-reexec
+systemctl --user daemon-reload
+systemctl --user enable flash-teensy.service
+
+echo "✅ One-time flash service scheduled to run after reboot."
+
 # ---------------------------------------------------------
-# Final Message
+# Final Message & Auto-Reboot
 # ---------------------------------------------------------
 echo ""
 echo "─────────────────────────────────────────────"
-echo "  Setup Complete — Time magic is in place."
+echo "  Setup Complete — Rebooting in 15 seconds..."
 echo "─────────────────────────────────────────────"
-echo "Teensy tools are installed, firmware is ready."
-echo "Your Raspberry Pi is now ready for testing."
+echo "Teensy will be flashed automatically on next boot (once)."
 echo ""
+sleep 15
+sudo reboot