--- a/source_sync_rls_25c/source/unisoc/multimedia/camera/libcamera/UT/OemUnitTest/OemUnitTest.cpp
+++ b/source_sync_rls_25c/source/unisoc/multimedia/camera/libcamera/UT/OemUnitTest/OemUnitTest.cpp
@@ -303,6 +303,7 @@
 
 int OemUnitTest::zslSnapshot() {
   int ret = CMR_CAMERA_SUCCESS;
+  Sprd_camera_state preview_state = getPreviewState();
 
   /*
    * ZSL is disabled on the current single-camera SBC bring-up path. Keep the
@@ -317,18 +318,26 @@
   mCaptureMode = CAMERA_NORMAL_MODE;
   mSprdZslEnabled = false;
 
-  if (!isPreviewing()) {
+  if (SPRD_IDLE == preview_state) {
     ret = startPreview();
     if (ret) {
       CMR_LOGE("zslSnapshot: fail to start preview dump");
       return ret;
     }
+  } else {
+    printf("OemUnitTest zslSnapshot reuse preview state %s\n",
+           getCameraStateStr(preview_state));
   }
 
   usleep(1000 * 1000);
   printf("OemUnitTest zslSnapshot preview-dump saved %d frame(s)\n",
          camera_dump_cnt_pre);
 
+  if (camera_dump_cnt_pre <= 0) {
+    CMR_LOGE("zslSnapshot: no preview frame dumped");
+    return CMR_CAMERA_FAIL;
+  }
+
   return CMR_CAMERA_SUCCESS;
 }
 
@@ -369,6 +378,7 @@
 
 int OemUnitTest::takePicture() {
   int ret = CMR_CAMERA_SUCCESS;
+  Sprd_camera_state preview_state = getPreviewState();
 
   /*
    * SBC bring-up path: the normal snapshot/JPEG pipeline still depends on
@@ -389,18 +399,26 @@
   mCaptureMode = CAMERA_NORMAL_MODE;
   mSprdZslEnabled = false;
 
-  if (!isPreviewing()) {
+  if (SPRD_IDLE == preview_state) {
     ret = startPreview();
     if (ret) {
       CMR_LOGE("takePicture: fail to start preview dump");
       return ret;
     }
+  } else {
+    printf("OemUnitTest takePicture reuse preview state %s\n",
+           getCameraStateStr(preview_state));
   }
 
   usleep(1000 * 1000);
   printf("OemUnitTest takePicture preview-dump saved %d frame(s)\n",
          camera_dump_cnt_pre);
 
+  if (camera_dump_cnt_pre <= 0) {
+    CMR_LOGE("takePicture: no preview frame dumped");
+    return CMR_CAMERA_FAIL;
+  }
+
   return CMR_CAMERA_SUCCESS;
 }