diff --git a/runtime/runtime.m b/runtime/runtime.m
index c838994cc378..8e829b39a987 100644
--- a/runtime/runtime.m
+++ b/runtime/runtime.m
@@ -131,7 +131,7 @@
 };
 
 enum InitializationFlags : int {
-	/* unused									= 0x01,*/
+	InitializationFlagsIsPartialStaticRegistrar = 0x01,
 	/* unused									= 0x02,*/
 	InitializationFlagsDynamicRegistrar			= 0x04,
 	/* unused									= 0x08,*/
@@ -1014,10 +1014,12 @@ -(void) xamarinSetGCHandle: (int) gc_handle;
 }
 
 void
-xamarin_add_registration_map (struct MTRegistrationMap *map)
+xamarin_add_registration_map (struct MTRegistrationMap *map, bool partial)
 {
 	// COOP: no managed memory access: any mode
 	options.RegistrationData = map;
+	if (partial)
+		options.flags = (InitializationFlags) (options.flags | InitializationFlagsIsPartialStaticRegistrar);
 
 	// Sort the type map according to Class
 	qsort (map->map, map->map_count, sizeof (MTClassMap), compare_mtclassmap);
@@ -1894,11 +1896,42 @@ -(void) xamarinSetGCHandle: (int) gc_handle;
 	set_raw_gchandle (self, gchandle);
 }
 
+static int
+find_user_type_index (MTClassMap *map, int lo, int hi, Class cls)
+{
+	if (hi >= lo) {
+		int mid = lo + (hi - lo) / 2;
+
+		if (map [mid].handle == cls)
+			return mid;
+
+		if ((intptr_t) map [mid].handle > (intptr_t) cls)
+			return find_user_type_index (map, lo, mid - 1, cls);
+
+		return find_user_type_index (map, mid + 1, hi, cls);
+	}
+
+	return -1;
+}
+
 static inline bool
 is_user_type (id self)
 {
+	Class cls = object_getClass (self);
+
+	if (options.RegistrationData != NULL && options.RegistrationData->map_count > 0) {
+		MTClassMap *map = options.RegistrationData->map;
+		int idx = find_user_type_index (map, 0, options.RegistrationData->map_count - 1, cls);
+		if (idx >= 0)
+			return (map [idx].flags & MTTypeFlagsUserType) == MTTypeFlagsUserType;
+		// If using the partial static registrar, we need to continue
+		// If full static registrar, we can return false
+		if ((options.flags & InitializationFlagsIsPartialStaticRegistrar) != InitializationFlagsIsPartialStaticRegistrar)
+			return false;
+	}
+
 	// COOP: no managed memory access: any mode
-	return class_getInstanceMethod (object_getClass (self), @selector (xamarinSetGCHandle:)) != NULL;
+	return class_getInstanceMethod (cls, @selector (xamarinSetGCHandle:)) != NULL;
 }
 
 #if defined(DEBUG_REF_COUNTING)
diff --git a/runtime/xamarin/runtime.h b/runtime/xamarin/runtime.h
index 277ff3fb884b..bfb443fd4d5b 100644
--- a/runtime/xamarin/runtime.h
+++ b/runtime/xamarin/runtime.h
@@ -71,6 +71,7 @@ static const uint32_t INVALID_TOKEN_REF = 0xFFFFFFFF;
 enum MTTypeFlags {
 	MTTypeFlagsNone = 0,
 	MTTypeFlagsCustomType = 1, // not a platform type
+	MTTypeFlagsUserType = 2, // not a wrapped type
 };
 
 typedef struct __attribute__((packed)) {
@@ -203,7 +204,7 @@ void			xamarin_unhandled_exception_handler (MonoObject *exc, gpointer user_data)
 void			xamarin_ftnptr_exception_handler (guint32 gchandle);
 void			xamarin_create_classes ();
 const char *	xamarin_skip_encoding_flags (const char *encoding);
-void			xamarin_add_registration_map (struct MTRegistrationMap *map);
+void			xamarin_add_registration_map (struct MTRegistrationMap *map, bool partial);
 uint32_t		xamarin_find_protocol_wrapper_type (uint32_t token_ref);
 void			xamarin_release_block_on_main_thread (void *obj);
 
diff --git a/src/ObjCRuntime/Runtime.cs b/src/ObjCRuntime/Runtime.cs
index 76901b0d5cd6..ab4a161aa2bb 100644
--- a/src/ObjCRuntime/Runtime.cs
+++ b/src/ObjCRuntime/Runtime.cs
@@ -76,6 +76,7 @@ internal enum MTTypeFlags : uint
 		{
 			None = 0,
 			CustomType = 1,
+			UserType = 2,
 		}
 
 		[StructLayout (LayoutKind.Sequential, Pack = 1)]
@@ -131,7 +132,7 @@ internal struct Trampolines {
 
 		[Flags]
 		internal enum InitializationFlags : int {
-			/* unused               = 0x01 */
+			IsPartialStaticRegistrar= 0x01,
 			/* unused				= 0x02,*/
 			DynamicRegistrar		= 0x04,
 			/* unused				= 0x08,*/
diff --git a/tools/common/StaticRegistrar.cs b/tools/common/StaticRegistrar.cs
index ec629c5dfdd9..52a26776fe12 100644
--- a/tools/common/StaticRegistrar.cs
+++ b/tools/common/StaticRegistrar.cs
@@ -2743,6 +2743,9 @@ void Specialize (AutoIndentStringBuilder sb)
 					if (!isPlatformType)
 						flags |= MTTypeFlags.CustomType;
 
+					if (!@class.IsWrapper && !@class.IsModel)
+						flags |= MTTypeFlags.UserType;
+
 					CheckNamespace (@class, exceptions);
 					token_ref = CreateTokenReference (@class.Type, TokenType.TypeDef);
 					map.AppendLine ("{{ NULL, 0x{1:X} /* #{3} '{0}' => '{2}' */, (MTTypeFlags) ({4}) /* {5} */ }},", 
@@ -3100,7 +3103,7 @@ void Specialize (AutoIndentStringBuilder sb)
 			map.AppendLine ("};");
 
 
-			map_init.AppendLine ("xamarin_add_registration_map (&__xamarin_registration_map);");
+			map_init.AppendLine ("xamarin_add_registration_map (&__xamarin_registration_map, {0});", string.IsNullOrEmpty (single_assembly) ? "false" : "true");
 			map_init.AppendLine ("}");
 
 			sb.WriteLine (map.ToString ());
@@ -4993,5 +4996,6 @@ internal enum MTTypeFlags : uint
 	{
 		None = 0,
 		CustomType = 1,
+		UserType = 2,
 	}
 }