diff --git a/src/ObjCRuntime/Dlfcn.cs b/src/ObjCRuntime/Dlfcn.cs
index 764c2e832770..578cd2ef03c1 100644
--- a/src/ObjCRuntime/Dlfcn.cs
+++ b/src/ObjCRuntime/Dlfcn.cs
@@ -211,6 +211,8 @@ public static ulong GetUInt64 (IntPtr handle, string symbol)
 			return (ulong) Marshal.ReadInt64 (indirect);
 		}
 
+#if !XAMCORE_4_0
+		[Obsolete ("Use 'SetInt64' for long values instead.")]
 		public static void SetUInt64 (IntPtr handle, string symbol, long value)
 		{
 			var indirect = dlsym (handle, symbol);
@@ -219,6 +221,16 @@ public static void SetUInt64 (IntPtr handle, string symbol, long value)
 
 			Marshal.WriteInt64 (indirect, (long) value);
 		}
+#endif
+
+		public static void SetUInt64 (IntPtr handle, string symbol, ulong value)
+		{
+			var indirect = dlsym (handle, symbol);
+			if (indirect == IntPtr.Zero)
+				return;
+
+			Marshal.WriteInt64 (indirect, (long) value);
+		}
 
 		public static void SetString (IntPtr handle, string symbol, string value)
 		{