diff --git a/BizHawk.Client.Common/RomLoader.cs b/BizHawk.Client.Common/RomLoader.cs
index fd85d7fa3b..ee235ce1eb 100644
--- a/BizHawk.Client.Common/RomLoader.cs
+++ b/BizHawk.Client.Common/RomLoader.cs
@@ -867,7 +867,7 @@ namespace BizHawk.Client.Common
 						{
 							// need to get rid of this hack at some point
 							rom = new RomGame(file);
-							((CoreFileProvider)nextComm.CoreFileProvider).SubfileDirectory = Path.GetDirectoryName(path.Replace("|", "")); // Dirty hack to get around archive filenames (since we are just getting the directory path, it is safe to mangle the filename
+							nextComm.CoreFileProvider.SubfileDirectory = Path.GetDirectoryName(path.Replace("|", "")); // Dirty hack to get around archive filenames (since we are just getting the directory path, it is safe to mangle the filename
 							byte[] romData = null;
 							byte[] xmlData = rom.FileData;
 
@@ -963,8 +963,8 @@ namespace BizHawk.Client.Common
 							// The user picked nothing in the Core picker
 							break;
 						case "83P":
-							var ti83Bios = ((CoreFileProvider)nextComm.CoreFileProvider).GetFirmware("TI83", "Rom", true);
-							var ti83BiosPath = ((CoreFileProvider)nextComm.CoreFileProvider).GetFirmwarePath("TI83", "Rom", true);
+							var ti83Bios = nextComm.CoreFileProvider.GetFirmware("TI83", "Rom", true);
+							var ti83BiosPath = nextComm.CoreFileProvider.GetFirmwarePath("TI83", "Rom", true);
 							using (var ti83AsHawkFile = new HawkFile(ti83BiosPath))
 							{
 								var ti83BiosAsRom = new RomGame(ti83AsHawkFile);
@@ -995,7 +995,7 @@ namespace BizHawk.Client.Common
 							else
 							{
 								// need to get rid of this hack at some point
-								((CoreFileProvider)nextComm.CoreFileProvider).SubfileDirectory = Path.GetDirectoryName(path.Replace("|", "")); // Dirty hack to get around archive filenames (since we are just getting the directory path, it is safe to mangle the filename
+								nextComm.CoreFileProvider.SubfileDirectory = Path.GetDirectoryName(path.Replace("|", "")); // Dirty hack to get around archive filenames (since we are just getting the directory path, it is safe to mangle the filename
 								var romData = isXml ? null : rom.FileData;
 								var xmlData = isXml ? rom.FileData : null;
 								var snes = new LibsnesCore(game, romData, xmlData, nextComm, GetCoreSettings<LibsnesCore>(), GetCoreSyncSettings<LibsnesCore>());
diff --git a/BizHawk.Emulation.Common/Interfaces/ICoreFileProvider.cs b/BizHawk.Emulation.Common/Interfaces/ICoreFileProvider.cs
index 5b3e523e97..1152bc3a1e 100644
--- a/BizHawk.Emulation.Common/Interfaces/ICoreFileProvider.cs
+++ b/BizHawk.Emulation.Common/Interfaces/ICoreFileProvider.cs
@@ -7,6 +7,8 @@ namespace BizHawk.Emulation.Common
 	/// </summary>
 	public interface ICoreFileProvider
 	{
+		string SubfileDirectory { get; set; }
+
 		/// <summary>
 		/// Produces a path to the requested file, expected to be parallel to the running rom. for example: cue+bin files or SFC+PCM (MSU-1 games)
 		/// </summary>