diff --git a/CMakeLists.txt b/CMakeLists.txt
index dd862bb154..f4fe0385d1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -659,7 +659,7 @@ if(UNIX)
     elseif(EMSCRIPTEN)
       # no need to link to system libs with emscripten
     elseif(QNXNTO)
-      # no need to link to system libs with QNX
+      set(OPENCV_LINKER_LIBS ${OPENCV_LINKER_LIBS} m)
     else()
       set(OPENCV_LINKER_LIBS ${OPENCV_LINKER_LIBS} dl m pthread rt)
     endif()
diff --git a/modules/core/src/parallel.cpp b/modules/core/src/parallel.cpp
index 81ddd0c5dd..1d4179b7b4 100644
--- a/modules/core/src/parallel.cpp
+++ b/modules/core/src/parallel.cpp
@@ -56,7 +56,7 @@
     #undef abs
 #endif
 
-#if defined __linux__ || defined __APPLE__ || defined __GLIBC__ \
+#if defined __unix__ || defined __APPLE__ || defined __GLIBC__ \
     || defined __HAIKU__ || defined __EMSCRIPTEN__ || defined __FreeBSD__ \
     || defined __OpenBSD__
     #include <unistd.h>
diff --git a/modules/core/src/system.cpp b/modules/core/src/system.cpp
index 777efceca0..ccb962e4ee 100644
--- a/modules/core/src/system.cpp
+++ b/modules/core/src/system.cpp
@@ -116,10 +116,14 @@ void* allocSingletonNewBuffer(size_t size) { return malloc(size); }
 #include <cstdlib>        // std::abort
 #endif
 
-#if defined __ANDROID__ || defined __linux__ || defined __FreeBSD__ || defined __OpenBSD__ || defined __HAIKU__ || defined __Fuchsia__
+#if defined __ANDROID__ || defined __unix__ || defined __FreeBSD__ || defined __OpenBSD__ || defined __HAIKU__ || defined __Fuchsia__
 #  include <unistd.h>
 #  include <fcntl.h>
+#if defined __QNXNTO__
+#  include <sys/elf.h>
+#else
 #  include <elf.h>
+#endif
 #if defined __ANDROID__ || defined __linux__
 #  include <linux/auxvec.h>
 #endif
@@ -130,7 +134,7 @@ void* allocSingletonNewBuffer(size_t size) { return malloc(size); }
 #endif
 
 
-#if (defined __ppc64__ || defined __PPC64__) && defined __linux__
+#if (defined __ppc64__ || defined __PPC64__) && defined __unix__
 # include "sys/auxv.h"
 # ifndef AT_HWCAP2
 #   define AT_HWCAP2 26
@@ -233,7 +237,7 @@ std::wstring GetTempFileNameWinRT(std::wstring prefix)
 #include "omp.h"
 #endif
 
-#if defined __linux__ || defined __APPLE__ || defined __EMSCRIPTEN__ || defined __FreeBSD__ || defined __GLIBC__ || defined __HAIKU__
+#if defined __unix__ || defined __APPLE__ || defined __EMSCRIPTEN__ || defined __FreeBSD__ || defined __GLIBC__ || defined __HAIKU__
 #include <unistd.h>
 #include <stdio.h>
 #include <sys/types.h>
@@ -600,7 +604,7 @@ struct HWFeatures
         have[CV_CPU_MSA] = true;
     #endif
 
-    #if (defined __ppc64__ || defined __PPC64__) && defined __linux__
+    #if (defined __ppc64__ || defined __PPC64__) && defined __unix__
         unsigned int hwcap = getauxval(AT_HWCAP);
         if (hwcap & PPC_FEATURE_HAS_VSX) {
             hwcap = getauxval(AT_HWCAP2);
@@ -814,12 +818,12 @@ int64 getTickCount(void)
     LARGE_INTEGER counter;
     QueryPerformanceCounter( &counter );
     return (int64)counter.QuadPart;
-#elif defined __linux || defined __linux__
+#elif defined __MACH__ && defined __APPLE__
+    return (int64)mach_absolute_time();
+#elif defined __unix__
     struct timespec tp;
     clock_gettime(CLOCK_MONOTONIC, &tp);
     return (int64)tp.tv_sec*1000000000 + tp.tv_nsec;
-#elif defined __MACH__ && defined __APPLE__
-    return (int64)mach_absolute_time();
 #else
     struct timeval tv;
     gettimeofday(&tv, NULL);
@@ -833,8 +837,6 @@ double getTickFrequency(void)
     LARGE_INTEGER freq;
     QueryPerformanceFrequency(&freq);
     return (double)freq.QuadPart;
-#elif defined __linux || defined __linux__
-    return 1e9;
 #elif defined __MACH__ && defined __APPLE__
     static double freq = 0;
     if( freq == 0 )
@@ -844,6 +846,8 @@ double getTickFrequency(void)
         freq = sTimebaseInfo.denom*1e9/sTimebaseInfo.numer;
     }
     return freq;
+#elif defined __unix__
+    return 1e9;
 #else
     return 1e6;
 #endif
diff --git a/modules/dnn/src/dnn.cpp b/modules/dnn/src/dnn.cpp
index 668cce8fa6..b1123e2195 100644
--- a/modules/dnn/src/dnn.cpp
+++ b/modules/dnn/src/dnn.cpp
@@ -2078,7 +2078,10 @@ struct Net::Impl : public detail::NetImplBase
 
             Ptr<InfEngineNgraphNode> ieNode = node.dynamicCast<InfEngineNgraphNode>();
             CV_Assert(!ieNode.empty());
-            ieNode->net->reset();
+
+            CV_Assert(ieNode->net);
+            InfEngineNgraphNet& ienet = *ieNode->net;
+            ienet.reset();
 
             for (it = layers.begin(); it != layers.end(); ++it)
             {
@@ -2095,16 +2098,26 @@ struct Net::Impl : public detail::NetImplBase
                 {
                     for (int i = 0; i < ld.outputBlobsWrappers.size(); ++i)
                     {
-                        InferenceEngine::DataPtr dataPtr = ngraphDataNode(ld.outputBlobsWrappers[i]);
-                        dataPtr->setName(ld.name);
+                        auto it = ienet.outputsDesc.find(ld.name);
+                        if (it != ienet.outputsDesc.end())
+                        {
+                            const InferenceEngine::TensorDesc& descriptor = it->second;
+                            InferenceEngine::DataPtr dataPtr = ngraphDataOutputNode(ld.outputBlobsWrappers[i], descriptor, ld.name);
+                            dataPtr->setName(ld.name);
+                        }
+                        else
+                        {
+                            InferenceEngine::DataPtr dataPtr = ngraphDataNode(ld.outputBlobsWrappers[i]);
+                            dataPtr->setName(ld.name);
+                        }
                     }
                 }
-                ieNode->net->addBlobs(ld.inputBlobsWrappers);
-                ieNode->net->addBlobs(ld.outputBlobsWrappers);
+                ienet.addBlobs(ld.inputBlobsWrappers);
+                ienet.addBlobs(ld.outputBlobsWrappers);
                 ld.skip = true;
             }
             layers[lastLayerId].skip = false;
-            ieNode->net->init((Target)preferableTarget);
+            ienet.init((Target)preferableTarget);
             return;
         }
 
@@ -4198,8 +4211,8 @@ void Net::forward(OutputArrayOfArrays outputBlobs,
         matvec.push_back(impl->getBlob(pins[i]));
     }
 
-    std::vector<Mat> & outputvec = *(std::vector<Mat> *)outputBlobs.getObj();
-    outputvec = matvec;
+    outputBlobs.create((int)matvec.size(), 1, CV_32F/*FIXIT*/, -1);  // allocate vector
+    outputBlobs.assign(matvec);
 }
 
 void Net::forward(std::vector<std::vector<Mat> >& outputBlobs,
diff --git a/modules/dnn/src/ie_ngraph.cpp b/modules/dnn/src/ie_ngraph.cpp
index 6f730a907a..a61766337e 100644
--- a/modules/dnn/src/ie_ngraph.cpp
+++ b/modules/dnn/src/ie_ngraph.cpp
@@ -792,21 +792,32 @@ void NgraphBackendLayer::forward(InputArrayOfArrays inputs, OutputArrayOfArrays
 }
 
 
-static InferenceEngine::Layout estimateLayout(const Mat& m)
+static InferenceEngine::Layout estimateLayout(int dims)
 {
-    if (m.dims == 4)
+    if (dims == 4)
         return InferenceEngine::Layout::NCHW;
-    else if (m.dims == 3)
+    else if (dims == 3)
         return InferenceEngine::Layout::CHW;
-    else if (m.dims == 2)
+    else if (dims == 2)
         return InferenceEngine::Layout::NC;
-    else if (m.dims == 1)
+    else if (dims == 1)
         return InferenceEngine::Layout::C;
-    else if (m.dims == 5)
+    else if (dims == 5)
         return InferenceEngine::Layout::NCDHW;
     else
         return InferenceEngine::Layout::ANY;
 }
+static inline
+InferenceEngine::Layout estimateLayout(size_t dims)
+{
+    return estimateLayout((int)dims);
+}
+
+static inline
+InferenceEngine::Layout estimateLayout(const Mat& m)
+{
+    return estimateLayout(m.dims);
+}
 
 static InferenceEngine::DataPtr wrapToInfEngineDataNode(const Mat& m, const std::string& name = "")
 {
@@ -842,6 +853,7 @@ InferenceEngine::Blob::Ptr wrapToNgraphBlob(const Mat& m, InferenceEngine::Layou
 
 NgraphBackendWrapper::NgraphBackendWrapper(int targetId, const cv::Mat& m)
     : BackendWrapper(DNN_BACKEND_INFERENCE_ENGINE_NGRAPH, targetId)
+    , host((Mat*)&m)
 {
     dataPtr = wrapToInfEngineDataNode(m);
     blob = wrapToNgraphBlob(m, estimateLayout(m));
@@ -893,7 +905,11 @@ InferenceEngine::Blob::Ptr copyBlob(const InferenceEngine::Blob::Ptr& blob)
         copy = InferenceEngine::make_shared_blob<uint8_t>(description);
     }
     else
-        CV_Error(Error::StsNotImplemented, "Unsupported blob precision");
+    {
+        std::ostringstream msg;
+        msg << precision;
+        CV_Error_(Error::StsNotImplemented, ("Unsupported blob precision: %s", msg.str().c_str()));
+    }
     copy->allocate();
     return copy;
 }
@@ -906,6 +922,66 @@ InferenceEngine::DataPtr ngraphDataNode(const Ptr<BackendWrapper>& ptr)
     return p->dataPtr;
 }
 
+static
+InferenceEngine::Blob::Ptr reallocateBlob(Mat &m, const InferenceEngine::TensorDesc& description)
+{
+    auto dims = description.getDims();
+    auto layout = estimateLayout(dims.size());
+    MatShape matShape(dims.begin(), dims.end());
+    if (description.getPrecision() == InferenceEngine::Precision::FP32)
+    {
+        m.create(matShape, CV_32FC1);
+        return InferenceEngine::make_shared_blob<float>(
+                {description.getPrecision(), dims, layout}, (float*)m.data);
+    }
+    else if (description.getPrecision() == InferenceEngine::Precision::I32)
+    {
+        m.create(matShape, CV_32SC1);
+        return InferenceEngine::make_shared_blob<int>(
+                {description.getPrecision(), dims, layout}, (int*)m.data);
+    }
+    else if (description.getPrecision() == InferenceEngine::Precision::U8)
+    {
+        m.create(matShape, CV_8UC1);
+        return InferenceEngine::make_shared_blob<uchar>(
+                {description.getPrecision(), dims, layout}, (uchar*)m.data);
+    }
+    std::ostringstream msg;
+    msg << "Unsupported IE precision: " << description.getPrecision();
+    CV_Error(Error::StsNotImplemented, msg.str());
+}
+
+InferenceEngine::DataPtr ngraphDataOutputNode(
+        const Ptr<BackendWrapper>& ptr,
+        const InferenceEngine::TensorDesc& description,
+        const std::string name)
+{
+    CV_Assert(!ptr.empty());
+    Ptr<NgraphBackendWrapper> p = ptr.dynamicCast<NgraphBackendWrapper>();
+    CV_Assert(!p.empty());
+    NgraphBackendWrapper& w = *p;
+    const InferenceEngine::TensorDesc& blobDesc = w.blob.get()->getTensorDesc();
+    auto dims = description.getDims();
+    bool reallocate = false;
+    if (blobDesc.getPrecision() != description.getPrecision())
+    {
+        reallocate = true;
+        CV_LOG_WARNING(NULL, "Reallocate output '" << name << "' blob due to wrong precision: " << blobDesc.getPrecision() << " => " << description.getPrecision() << "  ndims=" << dims.size());
+    }
+    if (dims.size() != blobDesc.getDims().size())
+    {
+        reallocate = true;
+        CV_LOG_WARNING(NULL, "Reallocate output '" << name << "' blob due to wrong dims: " << blobDesc.getDims().size() << " => " << dims.size());
+    }
+    if (reallocate)
+    {
+        auto layout = estimateLayout(dims.size());
+        w.dataPtr = InferenceEngine::DataPtr(new InferenceEngine::Data(name,
+               {description.getPrecision(), dims, layout}));
+        w.blob = reallocateBlob(*w.host, description);
+    }
+    return w.dataPtr;
+}
 
 void forwardNgraph(const std::vector<Ptr<BackendWrapper> >& outBlobsWrappers,
                       Ptr<BackendNode>& node, bool isAsync)
@@ -921,6 +997,13 @@ void InfEngineNgraphNet::reset()
     allBlobs.clear();
     infRequests.clear();
     isInit = false;
+
+    outputsDesc.clear();
+    for (const auto& it : cnn.getOutputsInfo())
+    {
+        const std::string& name = it.first;
+        outputsDesc.insert({name, it.second->getTensorDesc()});
+    }
 }
 
 void InfEngineNgraphNet::addBlobs(const std::vector<cv::Ptr<BackendWrapper> >& ptrs)
diff --git a/modules/dnn/src/ie_ngraph.hpp b/modules/dnn/src/ie_ngraph.hpp
index 7a8c4bef8d..617f1d4542 100644
--- a/modules/dnn/src/ie_ngraph.hpp
+++ b/modules/dnn/src/ie_ngraph.hpp
@@ -54,7 +54,8 @@ public:
     void setNodePtr(std::shared_ptr<ngraph::Node>* ptr);
 
     void reset();
-private:
+
+//private:
     detail::NetImplBase& netImpl_;
 
     void release();
@@ -89,6 +90,8 @@ private:
     bool hasNetOwner;
     std::vector<std::string> requestedOutputs;
     std::unordered_set<std::shared_ptr<ngraph::Node>> unconnectedNodes;
+
+    std::map<std::string, InferenceEngine::TensorDesc> outputsDesc;
 };
 
 class InfEngineNgraphNode : public BackendNode
@@ -121,12 +124,17 @@ public:
     virtual void copyToHost() CV_OVERRIDE;
     virtual void setHostDirty() CV_OVERRIDE;
 
+    Mat* host;
     InferenceEngine::DataPtr dataPtr;
     InferenceEngine::Blob::Ptr blob;
     AsyncArray futureMat;
 };
 
 InferenceEngine::DataPtr ngraphDataNode(const Ptr<BackendWrapper>& ptr);
+InferenceEngine::DataPtr ngraphDataOutputNode(
+        const Ptr<BackendWrapper>& ptr,
+        const InferenceEngine::TensorDesc& description,
+        const std::string name);
 
 // This is a fake class to run networks from Model Optimizer. Objects of that
 // class simulate responses of layers are imported by OpenCV and supported by
diff --git a/modules/dnn/src/onnx/onnx_importer.cpp b/modules/dnn/src/onnx/onnx_importer.cpp
index 8796b42321..94acd8f7fd 100644
--- a/modules/dnn/src/onnx/onnx_importer.cpp
+++ b/modules/dnn/src/onnx/onnx_importer.cpp
@@ -1425,6 +1425,45 @@ void ONNXImporter::handleNode(const opencv_onnx::NodeProto& node_proto_)
             }
             int outCn = layerParams.blobs.empty() ? outShapes[node_proto.input(1)][0] : layerParams.blobs[0].size[0];
             layerParams.set("num_output", outCn);
+
+            // Check for asymmetric padding in Conv2D
+            if (layerParams.has("pad"))
+            {
+                bool asymmetricPadding = false;
+                DictValue pads = layerParams.get("pad");
+                const int dims = pads.size() / 2;
+                for (int i = 0; i < dims; ++i)
+                {
+                    if (pads.get<int>(i) != pads.get<int>(i + dims))
+                    {
+                        asymmetricPadding = true;
+                        break;
+                    }
+                }
+                if (asymmetricPadding && pads.size() == 4) // [pad_t, pad_l, pad_b, pad_r]
+                {
+                    layerParams.erase("pad");
+                    // No paddings required for N, C axis
+                    std::vector<int> paddings(4, 0);
+                    // Add paddings for H, W axis
+                    for (int i = 0; i < dims; ++i)
+                    {
+                        paddings.push_back(pads.get<int>(i));
+                        paddings.push_back(pads.get<int>(dims + i));
+                    }
+                    LayerParams padLp;
+                    padLp.name = layerParams.name + "/pad";
+                    padLp.type = "Padding";
+                    padLp.set("paddings", DictValue::arrayInt(&paddings[0], paddings.size()));
+
+                    opencv_onnx::NodeProto proto;
+                    proto.add_input(node_proto.input(0));
+                    proto.add_output(padLp.name);
+
+                    addLayer(padLp, proto);
+                    node_proto.set_input(0, padLp.name);
+                }
+            }
         }
         else if (layer_type == "ConvTranspose")
         {
diff --git a/modules/dnn/test/test_ie_models.cpp b/modules/dnn/test/test_ie_models.cpp
index 760651c5c0..2846f9ae76 100644
--- a/modules/dnn/test/test_ie_models.cpp
+++ b/modules/dnn/test/test_ie_models.cpp
@@ -112,6 +112,25 @@ static const std::map<std::string, OpenVINOModelTestCaseInfo>& getOpenVINOTestMo
             "intel/age-gender-recognition-retail-0013/FP16/age-gender-recognition-retail-0013",
             "intel/age-gender-recognition-retail-0013/FP32/age-gender-recognition-retail-0013"
         }},
+#endif
+#if INF_ENGINE_RELEASE >= 2021020000
+        // OMZ: 2020.2
+        { "face-detection-0105", {
+            "intel/face-detection-0105/FP32/face-detection-0105",
+            "intel/face-detection-0105/FP16/face-detection-0105"
+        }},
+        { "face-detection-0106", {
+            "intel/face-detection-0106/FP32/face-detection-0106",
+            "intel/face-detection-0106/FP16/face-detection-0106"
+        }},
+#endif
+#if INF_ENGINE_RELEASE >= 2021040000
+        // OMZ: 2021.4
+        { "person-vehicle-bike-detection-2004", {
+            "intel/person-vehicle-bike-detection-2004/FP32/person-vehicle-bike-detection-2004",
+            "intel/person-vehicle-bike-detection-2004/FP16/person-vehicle-bike-detection-2004"
+            //"intel/person-vehicle-bike-detection-2004/FP16-INT8/person-vehicle-bike-detection-2004"
+        }},
 #endif
     };
 
@@ -145,10 +164,22 @@ inline static std::string getOpenVINOModel(const std::string &modelName, bool is
 static inline void genData(const InferenceEngine::TensorDesc& desc, Mat& m, Blob::Ptr& dataPtr)
 {
     const std::vector<size_t>& dims = desc.getDims();
-    m.create(std::vector<int>(dims.begin(), dims.end()), CV_32F);
-    randu(m, -1, 1);
-
-    dataPtr = make_shared_blob<float>(desc, (float*)m.data);
+    if (desc.getPrecision() == InferenceEngine::Precision::FP32)
+    {
+        m.create(std::vector<int>(dims.begin(), dims.end()), CV_32F);
+        randu(m, -1, 1);
+        dataPtr = make_shared_blob<float>(desc, (float*)m.data);
+    }
+    else if (desc.getPrecision() == InferenceEngine::Precision::I32)
+    {
+        m.create(std::vector<int>(dims.begin(), dims.end()), CV_32S);
+        randu(m, -100, 100);
+        dataPtr = make_shared_blob<int>(desc, (int*)m.data);
+    }
+    else
+    {
+        FAIL() << "Unsupported precision: " << desc.getPrecision();
+    }
 }
 
 void runIE(Target target, const std::string& xmlPath, const std::string& binPath,
@@ -254,7 +285,16 @@ void runIE(Target target, const std::string& xmlPath, const std::string& binPath
     BlobMap inputBlobs;
     for (auto& it : net.getInputsInfo())
     {
-        genData(it.second->getTensorDesc(), inputsMap[it.first], inputBlobs[it.first]);
+        const InferenceEngine::TensorDesc& desc = it.second->getTensorDesc();
+        genData(desc, inputsMap[it.first], inputBlobs[it.first]);
+        if (cvtest::debugLevel > 0)
+        {
+            const std::vector<size_t>& dims = desc.getDims();
+            std::cout << "Input: '" << it.first << "' precison=" << desc.getPrecision() << " dims=" << dims.size() << " [";
+            for (auto d : dims)
+                std::cout << " " << d;
+            std::cout << "]  ocv_mat=" << inputsMap[it.first].size << " of " << typeToString(inputsMap[it.first].type()) << std::endl;
+        }
     }
     infRequest.SetInput(inputBlobs);
 
@@ -263,7 +303,16 @@ void runIE(Target target, const std::string& xmlPath, const std::string& binPath
     BlobMap outputBlobs;
     for (auto& it : net.getOutputsInfo())
     {
-        genData(it.second->getTensorDesc(), outputsMap[it.first], outputBlobs[it.first]);
+        const InferenceEngine::TensorDesc& desc = it.second->getTensorDesc();
+        genData(desc, outputsMap[it.first], outputBlobs[it.first]);
+        if (cvtest::debugLevel > 0)
+        {
+            const std::vector<size_t>& dims = desc.getDims();
+            std::cout << "Output: '" << it.first << "' precison=" << desc.getPrecision() << " dims=" << dims.size() << " [";
+            for (auto d : dims)
+                std::cout << " " << d;
+            std::cout << "]  ocv_mat=" << outputsMap[it.first].size << " of " << typeToString(outputsMap[it.first].type()) << std::endl;
+        }
     }
     infRequest.SetOutput(outputBlobs);
 
@@ -284,6 +333,12 @@ void runCV(Backend backendId, Target targetId, const std::string& xmlPath, const
     net.setPreferableTarget(targetId);
 
     std::vector<String> outNames = net.getUnconnectedOutLayersNames();
+    if (cvtest::debugLevel > 0)
+    {
+        std::cout << "OpenCV output names: " << outNames.size() << std::endl;
+        for (auto name : outNames)
+            std::cout << "- " << name << std::endl;
+    }
     std::vector<Mat> outs;
     net.forward(outs, outNames);
 
@@ -307,13 +362,26 @@ TEST_P(DNNTestOpenVINO, models)
     ASSERT_FALSE(backendId != DNN_BACKEND_INFERENCE_ENGINE_NN_BUILDER_2019 && backendId != DNN_BACKEND_INFERENCE_ENGINE_NGRAPH) <<
         "Inference Engine backend is required";
 
-#if INF_ENGINE_VER_MAJOR_EQ(2021040000)
-    if (targetId == DNN_TARGET_MYRIAD && (
-            modelName == "person-detection-retail-0013" ||  // ncDeviceOpen:1013 Failed to find booted device after boot
-            modelName == "age-gender-recognition-retail-0013"  // ncDeviceOpen:1013 Failed to find booted device after boot
+#if INF_ENGINE_VER_MAJOR_GE(2021030000)
+    if (targetId == DNN_TARGET_MYRIAD && (false
+            || modelName == "person-detection-retail-0013"  // ncDeviceOpen:1013 Failed to find booted device after boot
+            || modelName == "age-gender-recognition-retail-0013"  // ncDeviceOpen:1013 Failed to find booted device after boot
+            || modelName == "face-detection-0105"  // get_element_type() must be called on a node with exactly one output
+            || modelName == "face-detection-0106"  // get_element_type() must be called on a node with exactly one output
+            || modelName == "person-vehicle-bike-detection-2004"  // 2021.4+: ncDeviceOpen:1013 Failed to find booted device after boot
         )
     )
         applyTestTag(CV_TEST_TAG_DNN_SKIP_IE_MYRIAD, CV_DNN_BACKEND_INFERENCE_ENGINE_NGRAPH, CV_TEST_TAG_DNN_SKIP_IE_VERSION);
+    if (targetId == DNN_TARGET_OPENCL && (false
+            || modelName == "face-detection-0106"  // Operation: 2278 of type ExperimentalDetectronPriorGridGenerator(op::v6) is not supported
+        )
+    )
+        applyTestTag(CV_TEST_TAG_DNN_SKIP_IE_OPENCL, CV_DNN_BACKEND_INFERENCE_ENGINE_NGRAPH, CV_TEST_TAG_DNN_SKIP_IE_VERSION);
+    if (targetId == DNN_TARGET_OPENCL_FP16 && (false
+            || modelName == "face-detection-0106"  // Operation: 2278 of type ExperimentalDetectronPriorGridGenerator(op::v6) is not supported
+        )
+    )
+        applyTestTag(CV_TEST_TAG_DNN_SKIP_IE_OPENCL_FP16, CV_DNN_BACKEND_INFERENCE_ENGINE_NGRAPH, CV_TEST_TAG_DNN_SKIP_IE_VERSION);
 #endif
 
 #if INF_ENGINE_VER_MAJOR_GE(2020020000)
@@ -352,6 +420,8 @@ TEST_P(DNNTestOpenVINO, models)
     if (targetId == DNN_TARGET_HDDL)
         releaseHDDLPlugin();
     EXPECT_NO_THROW(runIE(targetId, xmlPath, binPath, inputsMap, ieOutputsMap)) << "runIE";
+    if (targetId == DNN_TARGET_MYRIAD)
+        resetMyriadDevice();
     EXPECT_NO_THROW(runCV(backendId, targetId, xmlPath, binPath, inputsMap, cvOutputsMap)) << "runCV";
 
     double eps = 0;
@@ -359,6 +429,14 @@ TEST_P(DNNTestOpenVINO, models)
     if (targetId == DNN_TARGET_CPU && checkHardwareSupport(CV_CPU_AVX_512F))
         eps = 1e-5;
 #endif
+#if INF_ENGINE_VER_MAJOR_GE(2021030000)
+    if (targetId == DNN_TARGET_CPU && modelName == "face-detection-0105")
+        eps = 2e-4;
+#endif
+#if INF_ENGINE_VER_MAJOR_GE(2021040000)
+    if (targetId == DNN_TARGET_CPU && modelName == "person-vehicle-bike-detection-2004")
+        eps = 1e-6;
+#endif
 
     EXPECT_EQ(ieOutputsMap.size(), cvOutputsMap.size());
     for (auto& srcIt : ieOutputsMap)
diff --git a/modules/dnn/test/test_onnx_importer.cpp b/modules/dnn/test/test_onnx_importer.cpp
index b8f45a204c..69aac79cb5 100644
--- a/modules/dnn/test/test_onnx_importer.cpp
+++ b/modules/dnn/test/test_onnx_importer.cpp
@@ -112,6 +112,7 @@ TEST_P(Test_ONNX_layers, MaxPooling_2)
 TEST_P(Test_ONNX_layers, Convolution)
 {
     testONNXModels("convolution");
+    testONNXModels("conv_asymmetric_pads");
 }
 
 TEST_P(Test_ONNX_layers, Convolution_variable_weight)
diff --git a/modules/python/src2/cv2.cpp b/modules/python/src2/cv2.cpp
index 795afb13f2..55f512291b 100644
--- a/modules/python/src2/cv2.cpp
+++ b/modules/python/src2/cv2.cpp
@@ -2081,15 +2081,23 @@ static void OnChange(int pos, void *param)
 }
 
 #ifdef HAVE_OPENCV_HIGHGUI
+// workaround for #20408, use nullptr, set value later
+static int _createTrackbar(const String &trackbar_name, const String &window_name, int value, int count,
+                    TrackbarCallback onChange, PyObject* py_callback_info)
+{
+    int n = createTrackbar(trackbar_name, window_name, NULL, count, onChange, py_callback_info);
+    setTrackbarPos(trackbar_name, window_name, value);
+    return n;
+}
 static PyObject *pycvCreateTrackbar(PyObject*, PyObject *args)
 {
     PyObject *on_change;
     char* trackbar_name;
     char* window_name;
-    int *value = new int;
+    int value;
     int count;
 
-    if (!PyArg_ParseTuple(args, "ssiiO", &trackbar_name, &window_name, value, &count, &on_change))
+    if (!PyArg_ParseTuple(args, "ssiiO", &trackbar_name, &window_name, &value, &count, &on_change))
         return NULL;
     if (!PyCallable_Check(on_change)) {
         PyErr_SetString(PyExc_TypeError, "on_change must be callable");
@@ -2108,7 +2116,7 @@ static PyObject *pycvCreateTrackbar(PyObject*, PyObject *args)
     {
         registered_callbacks.insert(std::pair<std::string, PyObject*>(name, py_callback_info));
     }
-    ERRWRAP2(createTrackbar(trackbar_name, window_name, value, count, OnChange, py_callback_info));
+    ERRWRAP2(_createTrackbar(trackbar_name, window_name, value, count, OnChange, py_callback_info));
     Py_RETURN_NONE;
 }
 
diff --git a/platforms/winpack_dldt/build_package.py b/platforms/winpack_dldt/build_package.py
index 46926a38a5..ad2bbb796c 100644
--- a/platforms/winpack_dldt/build_package.py
+++ b/platforms/winpack_dldt/build_package.py
@@ -189,7 +189,10 @@ class BuilderDLDT:
         if self.srcdir is None:
             self.srcdir = prepare_dir(self.outdir / 'sources', clean=clean_src_dir)
         self.build_dir = prepare_dir(self.outdir / 'build', clean=self.config.clean_dldt)
-        self.sysrootdir = prepare_dir(self.outdir / 'sysroot', clean=self.config.clean_dldt)
+        self.sysrootdir = prepare_dir(self.outdir / 'sysroot', clean=self.config.clean_dldt or self.config.clean_dldt_sysroot)
+        if not (self.config.clean_dldt or self.config.clean_dldt_sysroot):
+            _ = prepare_dir(self.sysrootdir / 'bin', clean=True)  # always clean sysroot/bin (package files)
+            _ = prepare_dir(self.sysrootdir / 'etc', clean=True)  # always clean sysroot/etc (package files)
 
         if self.config.build_subst_drive:
             if os.path.exists(self.config.build_subst_drive + ':\\'):
@@ -485,8 +488,9 @@ def main():
     parser.add_argument('--cmake_option', action='append', help='Append OpenCV CMake option')
     parser.add_argument('--cmake_option_dldt', action='append', help='Append CMake option for DLDT project')
 
-    parser.add_argument('--clean_dldt', action='store_true', help='Clear DLDT build and sysroot directories')
-    parser.add_argument('--clean_opencv', action='store_true', help='Clear OpenCV build directory')
+    parser.add_argument('--clean_dldt', action='store_true', help='Clean DLDT build and sysroot directories')
+    parser.add_argument('--clean_dldt_sysroot', action='store_true', help='Clean DLDT sysroot directories')
+    parser.add_argument('--clean_opencv', action='store_true', help='Clean OpenCV build directory')
 
     parser.add_argument('--build_debug', action='store_true', help='Build debug binaries')
     parser.add_argument('--build_tests', action='store_true', help='Build OpenCV tests')
diff --git a/samples/cpp/grabcut.cpp b/samples/cpp/grabcut.cpp
index d3e3db49f9..25492166a7 100644
--- a/samples/cpp/grabcut.cpp
+++ b/samples/cpp/grabcut.cpp
@@ -107,12 +107,14 @@ void GCApplication::showImage() const
 
     Mat res;
     Mat binMask;
-    if( !isInitialized )
-        image->copyTo( res );
-    else
-    {
-        getBinMask( mask, binMask );
-        image->copyTo( res, binMask );
+    image->copyTo( res );
+    if( isInitialized ){
+        getBinMask( mask, binMask);
+
+        Mat black (binMask.rows, binMask.cols, CV_8UC3, cv::Scalar(0,0,0));
+        black.setTo(Scalar::all(255), binMask);
+
+        addWeighted(black, 0.5, res, 0.5, 0.0, res);
     }
 
     vector<Point>::const_iterator it;
@@ -201,24 +203,39 @@ void GCApplication::mouseClick( int event, int x, int y, int flags, void* )
     case EVENT_LBUTTONUP:
         if( rectState == IN_PROCESS )
         {
-            rect = Rect( Point(rect.x, rect.y), Point(x,y) );
-            rectState = SET;
-            setRectInMask();
-            CV_Assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() );
+            if(rect.x == x || rect.y == y){
+                rectState = NOT_SET;
+            }
+            else{
+                rect = Rect( Point(rect.x, rect.y), Point(x,y) );
+                rectState = SET;
+                setRectInMask();
+                CV_Assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() );
+            }
             showImage();
         }
         if( lblsState == IN_PROCESS )
         {
             setLblsInMask(flags, Point(x,y), false);
             lblsState = SET;
+            nextIter();
             showImage();
         }
+        else{
+            if(rectState == SET){
+                nextIter();
+                showImage();
+            }
+        }
         break;
     case EVENT_RBUTTONUP:
         if( prLblsState == IN_PROCESS )
         {
             setLblsInMask(flags, Point(x,y), true);
             prLblsState = SET;
+        }
+        if(rectState == SET){
+            nextIter();
             showImage();
         }
         break;