diff --git a/desmume/src/emufile.cpp b/desmume/src/emufile.cpp
index 1b2206895..d40102c7f 100644
--- a/desmume/src/emufile.cpp
+++ b/desmume/src/emufile.cpp
@@ -12,20 +12,6 @@ bool EMUFILE::readAllBytes(std::vector<u8>* dstbuf, const std::string& fname)
 	return true;
 }
 
-EMUFILE* EMUFILE::memwrap(EMUFILE* fp)
-{
-	EMUFILE_FILE* file;
-	EMUFILE_MEMORY* mem;
-	file = dynamic_cast<EMUFILE_FILE*>(fp);
-	mem = dynamic_cast<EMUFILE_MEMORY*>(fp);
-	if(mem) return mem;
-	mem = new EMUFILE_MEMORY(file->size());
-	if(file->size()==0) return mem;
-	file->fread(mem->buf(),file->size());
-	delete file;
-	return mem;
-}
-
 size_t EMUFILE_MEMORY::_fread(const void *ptr, size_t bytes){
 	u32 remain = len-pos;
 	u32 todo = std::min<u32>(remain,(u32)bytes);
@@ -62,4 +48,20 @@ void EMUFILE_FILE::truncate(s32 length)
 	fclose(fp);
 	fp = NULL;
 	open(fname.c_str(),mode);
-}
\ No newline at end of file
+}
+
+
+EMUFILE* EMUFILE_FILE::memwrap()
+{
+	EMUFILE_MEMORY* mem = new EMUFILE_MEMORY(size());
+	if(size()==0) return mem;
+	fread(mem->buf(),size());
+	return mem;
+}
+
+EMUFILE* EMUFILE_MEMORY::memwrap()
+{
+	return this;
+}
+
+	
\ No newline at end of file
diff --git a/desmume/src/emufile.h b/desmume/src/emufile.h
index 9fe452318..612feccad 100644
--- a/desmume/src/emufile.h
+++ b/desmume/src/emufile.h
@@ -43,8 +43,8 @@ public:
 	{}
 
 
-	//takes control of the provided EMUFILE and returns a new EMUFILE which is guranteed to be in memory
-	static EMUFILE* memwrap(EMUFILE* fp);
+	//returns a new EMUFILE which is guranteed to be in memory. the EMUFILE you call this on may be deleted. use the returned EMUFILE in its place
+	virtual EMUFILE* memwrap() = 0;
 
 	virtual ~EMUFILE() {}
 	
@@ -116,6 +116,8 @@ public:
 		if(ownvec) delete vec;
 	}
 
+	virtual EMUFILE* memwrap();
+
 	virtual void truncate(s32 length)
 	{
 		vec->resize(length);
@@ -241,6 +243,8 @@ public:
 		return fp; 
 	}
 
+	virtual EMUFILE* memwrap();
+
 	bool is_open() { return fp != NULL; }
 
 	virtual void truncate(s32 length);