diff --git a/src/Common/src/System/Diagnostics/Debug.cs b/src/Common/src/System/Diagnostics/Debug.cs
index 86edcb559..1093beca3 100644
--- a/src/Common/src/System/Diagnostics/Debug.cs
+++ b/src/Common/src/System/Diagnostics/Debug.cs
@@ -30,6 +30,10 @@ namespace System.Diagnostics
         {
             if (!condition)
             {
+#if CORERT
+                // CORERT-TODO
+                unsafe { *(int *)0 = 0; }
+#else
                 string stackTrace;
 
                 try
@@ -43,6 +47,7 @@ namespace System.Diagnostics
 
                 WriteAssert(stackTrace, message, detailMessage);
                 s_logger.ShowAssertDialog(stackTrace, message, detailMessage);
+#endif
             }
         }
 
diff --git a/src/ILToNative.Compiler/src/CppCodeGen/CppWriter.cs b/src/ILToNative.Compiler/src/CppCodeGen/CppWriter.cs
index 1969ccc4d..383e480c2 100644
--- a/src/ILToNative.Compiler/src/CppCodeGen/CppWriter.cs
+++ b/src/ILToNative.Compiler/src/CppCodeGen/CppWriter.cs
@@ -47,7 +47,6 @@ namespace ILToNative.CppCodeGen
 
             // TODO: For now, ensure that all types/methods referenced by temporary implementation in stubs.cpp are present
             var stringType = _compilation.TypeSystemContext.GetWellKnownType(WellKnownType.String);
-            _compilation.AddMethod(stringType.GetMethod("get_Chars", null));
             AddInstanceFields(stringType);
 
             var stringArrayType = stringType.MakeArrayType();
@@ -303,7 +302,7 @@ namespace ILToNative.CppCodeGen
                             importName = ecmaMethod.Name;
 
                         // TODO: hacky special-case
-                        if (importName != "memmove") // memmove is already declared by the CRT headers
+                        if (importName != "memmove" && importName != "malloc") // some methods are already declared by the CRT headers
                         {
                             builder.AppendLine(GetCppMethodDeclaration(method, false, importName));
                         }
diff --git a/src/ILToNative.Compiler/src/CppCodeGen/ILToCppImporter.cs b/src/ILToNative.Compiler/src/CppCodeGen/ILToCppImporter.cs
index ddd42b641..2789e6c23 100644
--- a/src/ILToNative.Compiler/src/CppCodeGen/ILToCppImporter.cs
+++ b/src/ILToNative.Compiler/src/CppCodeGen/ILToCppImporter.cs
@@ -1944,7 +1944,44 @@ namespace Internal.IL
 
         void ImportUnbox(int token, ILOpcode opCode)
         {
-            throw new NotImplementedException();
+            var type = ResolveTypeToken(token);
+
+            var obj = Pop();
+
+            if (opCode == ILOpcode.unbox)
+            {
+                PushTemp(StackValueKind.ByRef, type.MakeByRefType());
+            }
+            else
+            {
+                PushTemp(GetStackValueKind(type), type);
+            }
+
+            if (type.IsValueType)
+            {
+                // TODO: Unbox of nullable types
+                if (type.IsNullable)
+                    throw new NotImplementedException();
+
+                if (opCode == ILOpcode.unbox_any)
+                {
+                    string typeName = GetStackValueKindCPPTypeName(GetStackValueKind(type), type);
+                    Append("*(");
+                    Append(typeName);
+                    Append("*)");
+                }
+
+                Append("((void **)");
+                Append(obj.Value.Name);
+                Append("+1)");
+            }
+            else
+            {
+                // TODO: Cast
+                Append(obj.Value.Name);
+            }
+
+            Finish();
         }
 
         void ImportRefAnyVal(int token)
diff --git a/src/ILToNative/reproNative/main.cpp b/src/ILToNative/reproNative/main.cpp
index 79c121f98..b0299c285 100644
--- a/src/ILToNative/reproNative/main.cpp
+++ b/src/ILToNative/reproNative/main.cpp
@@ -287,11 +287,31 @@ extern "C" uint8_t RhIsValueType(MethodTable*)
     throw 42;
 }
 
-extern "C" intptr_t RhHandleAllocDependent(Object*, Object*)
+extern "C" uint8_t RhIsArray(MethodTable*)
 {
     throw 42;
 }
 
+extern "C" uint8_t RhTypeCast_AreTypesEquivalent(MethodTable*, MethodTable*)
+{
+    throw 42;
+}
+
+extern "C" void RhGetCurrentThreadStackTrace()
+{
+    throw 42;
+}
+
+extern "C" intptr_t RhHandleAlloc(Object * pObject, int type)
+{
+    return (intptr_t)CreateTypedHandle(g_HandleTableMap.pBuckets[0]->pTable[GetCurrentThreadHomeHeapNumber()], pObject, type);
+}
+
+extern "C" intptr_t RhHandleAllocDependent(Object* pPrimary, Object* pSecondary)
+{
+    return (intptr_t)CreateDependentHandle(g_HandleTableMap.pBuckets[0]->pTable[GetCurrentThreadHomeHeapNumber()], pPrimary, pSecondary);
+}
+
 extern "C" void RhpUniversalTransition()
 {
     throw 42;