diff --git a/src/p_djgpp2.cpp b/src/p_djgpp2.cpp
index a8483815..4ed94d7b 100644
--- a/src/p_djgpp2.cpp
+++ b/src/p_djgpp2.cpp
@@ -271,6 +271,7 @@ void PackDjgpp2::pack(OutputFile *fo)
     // filter
     Filter ft(opt->level);
     tryFilters(&ft, ibuf, usize - data->size, text->vaddr & ~0x1ff);
+    buildLoader(&ft);
 
     // compress
     ph.filter = ft.id;
diff --git a/src/p_djgpp2.h b/src/p_djgpp2.h
index 7b14f641..4c8d77fa 100644
--- a/src/p_djgpp2.h
+++ b/src/p_djgpp2.h
@@ -55,6 +55,7 @@ public:
 protected:
     virtual int buildLoader(const Filter *ft);
     virtual void handleStub(OutputFile *fo);
+    virtual bool readFileHeader();
 
     long coff_offset;
 
@@ -94,7 +95,6 @@ protected:
 
     external_scnhdr_t *text,*data,*bss;
 
-    bool readFileHeader();
     void stripDebug();
 };
 
diff --git a/src/p_tos.h b/src/p_tos.h
index f58785ad..df7b3c05 100644
--- a/src/p_tos.h
+++ b/src/p_tos.h
@@ -57,8 +57,8 @@ protected:
     virtual const upx_byte *getLoader() const;
     virtual int getLoaderSize() const;
 
-    bool readFileHeader();
-    bool checkFileHeader();
+    virtual bool readFileHeader();
+    virtual bool checkFileHeader();
 
     struct tos_header_t
     {
diff --git a/src/p_w32pe.cpp b/src/p_w32pe.cpp
index f16829f4..ab31e1eb 100644
--- a/src/p_w32pe.cpp
+++ b/src/p_w32pe.cpp
@@ -1619,6 +1619,7 @@ void PackW32Pe::pack(OutputFile *fo)
     Filter ft(opt->level);
     if (allow_filter)
         tryFilters(&ft, ibuf + ih.codebase, ih.codesize);
+    buildLoader(&ft);
 
     // compress
     ph.filter = ft.id;
@@ -1629,7 +1630,6 @@ void PackW32Pe::pack(OutputFile *fo)
 
     // verify filter
     ft.verifyUnfilter();
-    buildLoader(&ft);
 #else
     // new version using compressWithFilters()
 
diff --git a/src/p_w32pe.h b/src/p_w32pe.h
index 3260c8d3..499458e4 100644
--- a/src/p_w32pe.h
+++ b/src/p_w32pe.h
@@ -64,12 +64,12 @@ public:
         {  return (version == 12); }
 
 protected:
+    virtual bool readFileHeader();
     virtual bool testUnpackVersion(int version) const;
     virtual int buildLoader(const Filter *ft);
 
     unsigned pe_offset;
     bool isrtm;
-    bool readFileHeader();
 
     unsigned processImports();
     void processImports(unsigned);