diff --git a/Plugins/BASSMODS/BASSMODS/BASSDecoder.mm b/Plugins/BASSMODS/BASSMODS/BASSDecoder.mm
index 3398a249d..dd765ccfc 100755
--- a/Plugins/BASSMODS/BASSMODS/BASSDecoder.mm
+++ b/Plugins/BASSMODS/BASSMODS/BASSDecoder.mm
@@ -76,6 +76,8 @@ static void SyncProc( HSYNC handle, DWORD channel, DWORD data, void *user )
 
 - (BOOL)open:(id<CogSource>)s
 {
+    [self setSource:s];
+    
     [source seek:0 whence:SEEK_END];
     long size = [source tell];
     [source seek:0 whence:SEEK_SET];
@@ -89,14 +91,12 @@ static void SyncProc( HSYNC handle, DWORD channel, DWORD data, void *user )
         data = try_data;
     }
     
-    if (memcmp(data, "IMPM", 4) != 0) {
+    if (size < 4 || (memcmp(data, "mo3", 3) != 0 && memcmp(data, "IMPM", 4) != 0)) {
         ALog(@"BASS was passed a non-IT module");
         free(data);
         return NO;
     }
 	
-    [self setSource:s];
-    
     NSURL * url = [s url];
 	int track_num;
 	if ([[url fragment] length] == 0)