diff --git a/cmake/onnxruntime_unittests.cmake b/cmake/onnxruntime_unittests.cmake
index 6fb402be42..430d0cc3db 100644
--- a/cmake/onnxruntime_unittests.cmake
+++ b/cmake/onnxruntime_unittests.cmake
@@ -654,7 +654,9 @@ if(onnxruntime_USE_JSEP)
   list(APPEND onnxruntime_test_providers_libs onnxruntime_providers_js)
 endif()
 
-if(onnxruntime_USE_QNN)
+# QNN EP tests require CPU EP op implementations for accuracy evaluation, so disable on minimal
+# or reduced op builds.
+if(onnxruntime_USE_QNN AND NOT onnxruntime_MINIMAL_BUILD AND NOT onnxruntime_REDUCED_OPS_BUILD)
   list(APPEND onnxruntime_test_framework_src_patterns ${TEST_SRC_DIR}/providers/qnn/*)
   list(APPEND onnxruntime_test_framework_libs onnxruntime_providers_qnn)
   list(APPEND onnxruntime_test_providers_dependencies onnxruntime_providers_qnn)
diff --git a/onnxruntime/contrib_ops/cpu/cpu_contrib_kernels.cc b/onnxruntime/contrib_ops/cpu/cpu_contrib_kernels.cc
index 8aa885cf1e..e8ca437013 100644
--- a/onnxruntime/contrib_ops/cpu/cpu_contrib_kernels.cc
+++ b/onnxruntime/contrib_ops/cpu/cpu_contrib_kernels.cc
@@ -178,6 +178,7 @@ Status RegisterNchwcKernels(KernelRegistry& kernel_registry) {
 #ifdef MLAS_F16VEC_INTRINSICS_SUPPORTED
 Status RegisterFp16Kernels(KernelRegistry& kernel_registry) {
   static const BuildKernelCreateInfoFn function_table[] = {
+      BuildKernelCreateInfo<void>,  // default entry to avoid the list become empty after ops-reducing
       BuildKernelCreateInfo<ONNX_OPERATOR_TYPED_KERNEL_CLASS_NAME(kCpuExecutionProvider, kMSDomain, 1, MLFloat16, FusedConv)>,
       BuildKernelCreateInfo<ONNX_OPERATOR_TYPED_KERNEL_CLASS_NAME(kCpuExecutionProvider, kMSDomain, 1, MLFloat16, NhwcFusedConv)>,
       BuildKernelCreateInfo<ONNX_OPERATOR_TYPED_KERNEL_CLASS_NAME(kCpuExecutionProvider, kMSInternalNHWCDomain, 12, MLFloat16, MaxPool)>,
diff --git a/onnxruntime/core/providers/cpu/cpu_execution_provider.cc b/onnxruntime/core/providers/cpu/cpu_execution_provider.cc
index b8d5a7852a..9147107ac5 100644
--- a/onnxruntime/core/providers/cpu/cpu_execution_provider.cc
+++ b/onnxruntime/core/providers/cpu/cpu_execution_provider.cc
@@ -2711,6 +2711,7 @@ Status RegisterOnnxOperatorKernels(KernelRegistry& kernel_registry) {
 #ifdef MLAS_F16VEC_INTRINSICS_SUPPORTED
 Status RegisterFp16Kernels(KernelRegistry& kernel_registry) {
   static const BuildKernelCreateInfoFn function_table[] = {
+      BuildKernelCreateInfo<void>,  // default entry to avoid the list become empty after ops-reducing
       BuildKernelCreateInfo<ONNX_OPERATOR_TYPED_KERNEL_CLASS_NAME(kCpuExecutionProvider, kOnnxDomain, 1, MLFloat16,
                                                                   GlobalAveragePool)>,
       BuildKernelCreateInfo<ONNX_OPERATOR_TYPED_KERNEL_CLASS_NAME(kCpuExecutionProvider, kOnnxDomain, 11, MLFloat16,