diff --git a/server/SHServ/Controllers/DevicesRESTAPIController.php b/server/SHServ/Controllers/DevicesRESTAPIController.php
index 7297a7e..5dec3ee 100644
--- a/server/SHServ/Controllers/DevicesRESTAPIController.php
+++ b/server/SHServ/Controllers/DevicesRESTAPIController.php
@@ -10,29 +10,50 @@
 class DevicesRESTAPIController extends \SHServ\Middleware\Controller {
 	protected function withScanLock(callable $callback) {
 		$lockFile = dirname(__DIR__, 2) . '/Cache/scan.lock';
+		$debugLog = dirname(__DIR__, 2) . '/Cache/scan-debug.log';
 
-		// Если lock устарел (старше 120 сек) — считаем его мёртвым
+		$log = function($msg) use ($debugLog) {
+			$line = date('Y-m-d H:i:s') . ' [' . getmypid() . '] ' . $msg . PHP_EOL;
+			@file_put_contents($debugLog, $line, FILE_APPEND | LOCK_EX);
+		};
+
 		if (file_exists($lockFile) && (time() - filemtime($lockFile)) > 120) {
+			$log('stale lock detected, unlinking');
 			@unlink($lockFile);
 		}
 
 		$fp = @fopen($lockFile, 'c+');
-
 		if (!$fp || !flock($fp, LOCK_EX | LOCK_NB)) {
+			$log('lock busy (fp=' . var_export($fp, true) . '), returning 400');
 			return $this -> utils() -> response_error("scan_in_progress");
 		}
 
 		ftruncate($fp, 0);
 		fwrite($fp, getmypid());
 		fflush($fp);
-		touch($lockFile); // обновить mtime
+		touch($lockFile);
 
-		try {
-			return $callback();
-		} finally {
+		$lockReleased = false;
+		$releaseLock = function() use ($fp, $lockFile, $log, &$lockReleased) {
+			if ($lockReleased) return;
+			$lockReleased = true;
 			flock($fp, LOCK_UN);
 			fclose($fp);
 			@unlink($lockFile);
+			$log('lock released');
+		};
+		register_shutdown_function($releaseLock);
+
+		try {
+			$log('lock acquired, starting scan');
+			$result = $callback();
+			$log('scan finished normally');
+			return $result;
+		} catch (\Throwable $e) {
+			$log('scan exception: ' . $e -> getMessage());
+			throw $e;
+		} finally {
+			$releaseLock();
 		}
 	}
 
diff --git a/server/SHServ/Tools/DeviceScanner.php b/server/SHServ/Tools/DeviceScanner.php
index 14b361d..ba08e83 100644
--- a/server/SHServ/Tools/DeviceScanner.php
+++ b/server/SHServ/Tools/DeviceScanner.php
@@ -78,7 +78,7 @@
     $batches = array_chunk($ips, self::BATCH_SIZE);
 
     foreach ($batches as $batch) {
-      if ((connection_status() !== CONNECTION_NORMAL)) {
+      if (connection_aborted() || connection_status() !== CONNECTION_NORMAL) {
         return $all_devices;
       }
       $batch_devices = $this -> scan_batch($batch, $port, $timeout);
@@ -96,7 +96,7 @@
   private function scan_batch(array $ips, int $port, float $timeout): array {
     $devices = $this -> scan_batch_multi($ips, $port, $timeout);
 
-    if ((connection_status() !== CONNECTION_NORMAL)) {
+    if (connection_aborted() || connection_status() !== CONNECTION_NORMAL) {
       return $devices;
     }
 
@@ -156,7 +156,7 @@
         break;
       }
 
-      if ((connection_status() !== CONNECTION_NORMAL)) {
+      if (connection_aborted() || connection_status() !== CONNECTION_NORMAL) {
         break;
       }