diff --git a/AppImage/scripts/flask_server.py b/AppImage/scripts/flask_server.py
index 23b187de..b9ca259b 100644
--- a/AppImage/scripts/flask_server.py
+++ b/AppImage/scripts/flask_server.py
@@ -6698,21 +6698,27 @@ def api_smart_status(disk_name):
 def api_smart_run_test(disk_name):
     """Start a SMART self-test on a disk."""
     try:
+        logging.info(f"[SMART Test] Starting test for disk: {disk_name}")
+        
         # Validate disk name (security)
         if not re.match(r'^[a-zA-Z0-9]+$', disk_name):
+            logging.warning(f"[SMART Test] Invalid disk name rejected: {disk_name}")
             return jsonify({'error': 'Invalid disk name'}), 400
         
         device = f'/dev/{disk_name}'
         if not os.path.exists(device):
+            logging.warning(f"[SMART Test] Device not found: {device}")
             return jsonify({'error': 'Device not found'}), 404
         
         data = request.get_json() or {}
         test_type = data.get('test_type', 'short')
+        logging.info(f"[SMART Test] Test type: {test_type}, Device: {device}")
         
         if test_type not in ('short', 'long'):
             return jsonify({'error': 'Invalid test type. Use "short" or "long"'}), 400
         
         is_nvme = _is_nvme(disk_name)
+        logging.info(f"[SMART Test] Is NVMe: {is_nvme}")
         
         # Check tools and auto-install if missing
         tools = _ensure_smart_tools(install_if_missing=True)
@@ -6728,7 +6734,7 @@ def api_smart_run_test(disk_name):
             # NVMe: self-test-code 1=short, 2=long
             code = 1 if test_type == 'short' else 2
             
-            # First check if device supports self-test
+            # First check if device is accessible
             check_proc = subprocess.run(
                 ['nvme', 'id-ctrl', device],
                 capture_output=True, text=True, timeout=10
@@ -6736,24 +6742,48 @@ def api_smart_run_test(disk_name):
             if check_proc.returncode != 0:
                 return jsonify({'error': f'Cannot access NVMe device: {check_proc.stderr.strip() or "Device not responding"}'}), 500
             
+            # Check if device supports self-test by looking at OACS field
+            # OACS bit 4 (0x10) indicates Device Self-test support
+            oacs_output = check_proc.stdout
+            supports_selftest = True  # Assume supported by default
+            for line in oacs_output.split('\n'):
+                if 'oacs' in line.lower():
+                    try:
+                        # Parse OACS value (usually in hex)
+                        oacs_val = int(line.split(':')[-1].strip(), 0)
+                        if not (oacs_val & 0x10):
+                            supports_selftest = False
+                    except (ValueError, IndexError):
+                        pass
+                    break
+            
+            if not supports_selftest:
+                return jsonify({'error': 'This NVMe device does not support self-test (OACS bit 4 not set)'}), 400
+            
+            logging.info(f"[SMART Test] Running: nvme device-self-test {device} --self-test-code={code}")
             proc = subprocess.run(
                 ['nvme', 'device-self-test', device, f'--self-test-code={code}'],
                 capture_output=True, text=True, timeout=30
             )
+            logging.info(f"[SMART Test] Result: returncode={proc.returncode}, stdout={proc.stdout[:200] if proc.stdout else ''}, stderr={proc.stderr[:200] if proc.stderr else ''}")
             
             if proc.returncode != 0:
                 error_msg = proc.stderr.strip() or proc.stdout.strip() or 'Unknown error'
                 # Some NVMe devices don't support self-test
-                if 'not support' in error_msg.lower() or 'invalid' in error_msg.lower():
+                if 'not support' in error_msg.lower() or 'invalid' in error_msg.lower() or 'operation' in error_msg.lower():
                     return jsonify({'error': f'This NVMe device does not support self-test: {error_msg}'}), 400
+                # Check for permission errors
+                if 'permission' in error_msg.lower() or 'operation not permitted' in error_msg.lower():
+                    return jsonify({'error': f'Permission denied. Run as root: {error_msg}'}), 403
                 return jsonify({'error': f'Failed to start test: {error_msg}'}), 500
             
             # Start background monitor to save JSON when test completes
+            # Use 'nvme self-test-log' to check test status (not device-self-test)
             sleep_interval = 10 if test_type == 'short' else 60
             subprocess.Popen(
                 f'''
                 sleep 5
-                while nvme device-self-test {device} --self-test-code=0 2>/dev/null | grep -qi 'in progress'; do
+                while nvme self-test-log {device} 2>/dev/null | grep -qi 'in progress\\|operation in progress'; do
                     sleep {sleep_interval}
                 done
                 nvme smart-log -o json {device} > {json_path} 2>/dev/null