diff --git a/BizHawk.Client.Common/movie/conversions/MovieConversionExtensions.cs b/BizHawk.Client.Common/movie/conversions/MovieConversionExtensions.cs
index 97987623d3..284e9d6233 100644
--- a/BizHawk.Client.Common/movie/conversions/MovieConversionExtensions.cs
+++ b/BizHawk.Client.Common/movie/conversions/MovieConversionExtensions.cs
@@ -4,6 +4,7 @@ using System.Linq;
 
 using BizHawk.Emulation.Common;
 using BizHawk.Emulation.Cores.Nintendo.Gameboy;
+using BizHawk.Emulation.Cores.Sega.MasterSystem;
 using BizHawk.Emulation.Common.IEmulatorExtensions;
 
 namespace BizHawk.Client.Common.MovieConversionExtensions
@@ -311,6 +312,11 @@ namespace BizHawk.Client.Common.MovieConversionExtensions
 				movie.HeaderEntries.Add("IsCGBMode", "1");
 			}
 
+			if (Global.Emulator is SMS && (Global.Emulator as SMS).IsSG1000)
+			{
+				movie.HeaderEntries.Add("IsSGMode", "1");
+			}
+
 			movie.Core = ((CoreAttributes)Attribute
 				.GetCustomAttribute(Global.Emulator.GetType(), typeof(CoreAttributes)))
 				.CoreName;