diff --git a/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.pbxproj b/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.pbxproj
index ba518c6..a66977b 100644
--- a/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.pbxproj
+++ b/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.pbxproj
@@ -679,10 +679,15 @@
 					"$(inherited)",
 					"$(PROJECT_DIR)",
 				);
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"INFERENCE_HELPER_ENABLE_MNN=1",
+					"IOS_CPU_FORWARD=1",
+				);
 				GENERATE_INFOPLIST_FILE = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)/../../cpp/src";
 				INFOPLIST_KEY_NSHumanReadableCopyright = "";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
@@ -713,10 +718,15 @@
 					"$(inherited)",
 					"$(PROJECT_DIR)",
 				);
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"INFERENCE_HELPER_ENABLE_MNN=1",
+					"IOS_CPU_FORWARD=1",
+				);
 				GENERATE_INFOPLIST_FILE = YES;
 				HEADER_SEARCH_PATHS = "$(SRCROOT)/../../cpp/src";
 				INFOPLIST_KEY_NSHumanReadableCopyright = "";
 				INSTALL_PATH = "$(LOCAL_LIBRARY_DIR)/Frameworks";
+				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
 				LD_RUNPATH_SEARCH_PATHS = (
 					"$(inherited)",
 					"@executable_path/Frameworks",
diff --git a/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.xcworkspace/xcuserdata/tunm.xcuserdatad/UserInterfaceState.xcuserstate b/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.xcworkspace/xcuserdata/tunm.xcuserdatad/UserInterfaceState.xcuserstate
index 83450d9..42a1115 100644
Binary files a/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.xcworkspace/xcuserdata/tunm.xcuserdatad/UserInterfaceState.xcuserstate and b/Prj-iOS/hyperlpr3/hyperlpr3.xcodeproj/project.xcworkspace/xcuserdata/tunm.xcuserdatad/UserInterfaceState.xcuserstate differ
diff --git a/cpp/src/buffer_module/camera_buffer.cpp b/cpp/src/buffer_module/camera_buffer.cpp
index 8439a22..9433639 100644
--- a/cpp/src/buffer_module/camera_buffer.cpp
+++ b/cpp/src/buffer_module/camera_buffer.cpp
@@ -43,9 +43,9 @@ void CameraBuffer::SetDataFormat(DATA_FORMAT data_format) {
     if (data_format == BGRA) {
         config_.sourceFormat = MNN::CV::BGRA;
     }
-    if (data_format == YCrCb) {
-        config_.sourceFormat = MNN::CV::YCrCb;
-    }
+//    if (data_format == YCrCb) {
+//        config_.sourceFormat = MNN::CV::YCrCb;
+//    }
 }
 
 cv::Mat CameraBuffer::GetAffineRGBImage(const cv::Mat &affine_matrix, const int width_out, const int height_out) const {
@@ -233,4 +233,4 @@ int CameraBuffer::GetRotationMode() const{
     return rotation_mode_;
 }
 
-}
\ No newline at end of file
+}
diff --git a/cpp/src/context_module/hyper_lpr_context.cpp b/cpp/src/context_module/hyper_lpr_context.cpp
index 1f0d157..d455420 100644
--- a/cpp/src/context_module/hyper_lpr_context.cpp
+++ b/cpp/src/context_module/hyper_lpr_context.cpp
@@ -112,6 +112,7 @@ void HyperLPRContext::operator()(CameraBuffer &buffer) {
             obj.type = type;
 
             strcpy(obj.code, text_line.code.c_str());
+//            printf("%s\n", obj.code);
 //        obj.code = text_line.code;
 
 //        cv::imshow("align_image_pad", align_image_pad);
diff --git a/cpp/src/inference_helper_module/inference_helper_mnn.cpp b/cpp/src/inference_helper_module/inference_helper_mnn.cpp
index cbc8317..2e430aa 100644
--- a/cpp/src/inference_helper_module/inference_helper_mnn.cpp
+++ b/cpp/src/inference_helper_module/inference_helper_mnn.cpp
@@ -176,7 +176,12 @@ int32_t InferenceHelperMnn::Initialize(const std::string& model_filename, std::v
     }
 
     MNN::ScheduleConfig scheduleConfig;
+#ifdef IOS_CPU_FORWARD
+    PRINT("ios use cpu backend.");
+    scheduleConfig.type = MNN_FORWARD_CPU;
+#else
     scheduleConfig.type = MNN_FORWARD_AUTO;
+#endif
     scheduleConfig.numThread = num_threads_;    // it seems, setting 1 has better performance on Android
     // MNN::BackendConfig bnconfig;
     // bnconfig.power = MNN::BackendConfig::Power_High;