diff --git a/src/p_com.cpp b/src/p_com.cpp
index 6bd46db9..ce294c02 100644
--- a/src/p_com.cpp
+++ b/src/p_com.cpp
@@ -221,6 +221,10 @@ void PackCom::pack(OutputFile *fo)
 
     // verify
     verifyOverlappingDecompression(&obuf, overlapoh);
+
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
diff --git a/src/p_djgpp2.cpp b/src/p_djgpp2.cpp
index 14435d67..deb08316 100644
--- a/src/p_djgpp2.cpp
+++ b/src/p_djgpp2.cpp
@@ -368,6 +368,10 @@ void PackDjgpp2::pack(OutputFile *fo)
     // handle overlay
     // FIXME: only Allegro pakfiles are supported
     handle_allegropak(fi,fo);
+
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
diff --git a/src/p_exe.cpp b/src/p_exe.cpp
index f5c62732..10c785c3 100644
--- a/src/p_exe.cpp
+++ b/src/p_exe.cpp
@@ -516,6 +516,10 @@ void PackExe::pack(OutputFile *fo)
     // copy the overlay
     copyOverlay(fo, overlay, &obuf);
 //fprintf (stderr,"%x %x\n",relocsize,ph.u_len);
+
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
diff --git a/src/p_lx_elf.cpp b/src/p_lx_elf.cpp
index dfac13ca..88685443 100644
--- a/src/p_lx_elf.cpp
+++ b/src/p_lx_elf.cpp
@@ -360,8 +360,8 @@ void PackLinuxI386elf::pack(OutputFile *fo)
 
     updateLoader(fo);
 
-    // finally check compression ratio
-    if (!super::checkCompressionRatio(ph.u_len, fo->getBytesWritten()))
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
         throwNotCompressible();
 }
 
diff --git a/src/p_tmt.cpp b/src/p_tmt.cpp
index 6601106d..b3de260f 100644
--- a/src/p_tmt.cpp
+++ b/src/p_tmt.cpp
@@ -263,6 +263,10 @@ void PackTmt::pack(OutputFile *fo)
 
     // copy the overlay
     copyOverlay(fo, overlay, &obuf);
+
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
diff --git a/src/p_tos.cpp b/src/p_tos.cpp
index 8445d752..be15fd2a 100644
--- a/src/p_tos.cpp
+++ b/src/p_tos.cpp
@@ -542,6 +542,10 @@ void PackTos::pack(OutputFile *fo)
 
     // copy the overlay
     copyOverlay(fo, overlay, &obuf);
+
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
diff --git a/src/p_unix.cpp b/src/p_unix.cpp
index 5d800f97..afe02a53 100644
--- a/src/p_unix.cpp
+++ b/src/p_unix.cpp
@@ -196,8 +196,8 @@ void PackUnix::pack(OutputFile *fo)
 
     updateLoader(fo);
 
-    // finally check compression ratio
-    if (!Packer::checkCompressionRatio(ph.u_len, fo->getBytesWritten()))
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
         throwNotCompressible();
 }
 
diff --git a/src/p_vmlinz.cpp b/src/p_vmlinz.cpp
index f9a75d6a..fa84e020 100644
--- a/src/p_vmlinz.cpp
+++ b/src/p_vmlinz.cpp
@@ -71,11 +71,17 @@ const int *PackVmlinuzI386::getFilters() const
 }
 
 
+bool PackVmlinuzI386::canPack()
+{
+    return readFileHeader() == getFormat();
+}
+
+
 /*************************************************************************
-// common routines
+// common util routines
 **************************************************************************/
 
-int PackVmlinuzI386::readHeader()
+int PackVmlinuzI386::readFileHeader()
 {
     boot_sect_t h;
 
@@ -95,7 +101,7 @@ int PackVmlinuzI386::readHeader()
 }
 
 
-// read kernel into obuf, gzip-uncompress into ibuf,
+// read full kernel into obuf, gzip-uncompress into ibuf,
 // return uncompressed size
 int PackVmlinuzI386::uncompressKernel()
 {
@@ -147,8 +153,9 @@ void PackVmlinuzI386::readKernel()
     if (klen <= 0)
         throwCantPack("kernel decompression failed");
 
-    // OutputFile::dump("kernel.img", ibuf, ulen);
+    //OutputFile::dump("kernel.img", ibuf, klen);
 
+    // copy the setup boot code
     setup_buf.alloc(setup_size);
     memcpy(setup_buf, obuf, setup_size);
 
@@ -163,12 +170,6 @@ void PackVmlinuzI386::readKernel()
 // vmlinuz specific
 **************************************************************************/
 
-bool PackVmlinuzI386::canPack()
-{
-    return readHeader() == UPX_F_VMLINUZ_i386;
-}
-
-
 void PackVmlinuzI386::pack(OutputFile *fo)
 {
     readKernel();
@@ -203,9 +204,15 @@ void PackVmlinuzI386::pack(OutputFile *fo)
     fo->write(setup_buf, setup_buf.getSize());
     fo->write(loader, lsize);
     fo->write(obuf, clen);
+#if 0
+    printf("%-13s: setup        : %8ld bytes\n", getName(), (long) setup_buf.getSize());
+    printf("%-13s: loader       : %8ld bytes\n", getName(), (long) lsize);
+    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) clen);
+#endif
 
-    //if (!checkCompressionRatio(file_size, fo->getBytesWritten()))
-    //    throwNotCompressible();
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
@@ -213,12 +220,6 @@ void PackVmlinuzI386::pack(OutputFile *fo)
 // bvmlinuz specific
 **************************************************************************/
 
-bool PackBvmlinuzI386::canPack()
-{
-    return readHeader() == UPX_F_BVMLINUZ_i386;
-}
-
-
 void PackBvmlinuzI386::pack(OutputFile *fo)
 {
     readKernel();
@@ -277,12 +278,19 @@ void PackBvmlinuzI386::pack(OutputFile *fo)
     fo->write(loader, e_len);
     fo->write(obuf, clen);
     fo->write(loader + e_len, lsize - e_len);
+#if 0
+    printf("%-13s: setup        : %8ld bytes\n", getName(), (long) setup_buf.getSize());
+    printf("%-13s: entry        : %8ld bytes\n", getName(), (long) e_len);
+    printf("%-13s: compressed   : %8ld bytes\n", getName(), (long) clen);
+    printf("%-13s: decompressor : %8ld bytes\n", getName(), (long) (lsize - e_len));
+#endif
 
     // verify
     verifyOverlappingDecompression(&obuf, overlapoh);
 
-    //if (!checkCompressionRatio(file_size, fo->getBytesWritten()))
-    //    throwNotCompressible();
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
@@ -295,6 +303,7 @@ int PackVmlinuzI386::canUnpack()
     return false;
 }
 
+
 void PackVmlinuzI386::unpack(OutputFile *)
 {
     // no uncompression support for this format, so that
diff --git a/src/p_vmlinz.h b/src/p_vmlinz.h
index 303c0664..49082ae7 100644
--- a/src/p_vmlinz.h
+++ b/src/p_vmlinz.h
@@ -52,7 +52,7 @@ public:
     virtual int canUnpack();
 
 protected:
-    virtual int readHeader();
+    virtual int readFileHeader();
     virtual int uncompressKernel();
     virtual void readKernel();
 
@@ -98,8 +98,6 @@ public:
     virtual const char *getName() const { return "bvmlinuz/386"; }
 
     virtual void pack(OutputFile *fo);
-
-    virtual bool canPack();
 };
 
 
diff --git a/src/p_w32pe.cpp b/src/p_w32pe.cpp
index d0d03e43..876ca776 100644
--- a/src/p_w32pe.cpp
+++ b/src/p_w32pe.cpp
@@ -1902,8 +1902,8 @@ void PackW32Pe::pack(OutputFile *fo)
     // copy the overlay
     copyOverlay(fo, overlay, &obuf);
 
-    // finally check compresion ratio
-    if (!checkCompressionRatio(file_size, fo->getBytesWritten()))
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
         throwNotCompressible();
 }
 
diff --git a/src/p_wcle.cpp b/src/p_wcle.cpp
index 4ca9ab4d..a7ec8949 100644
--- a/src/p_wcle.cpp
+++ b/src/p_wcle.cpp
@@ -544,6 +544,10 @@ void PackWcle::pack(OutputFile *fo)
     const unsigned overlay = file_size - overlaystart - ih.non_resident_name_table_length;
     checkOverlay(overlay);
     copyOverlay(fo, overlay, &oimage);
+
+    // finally check the compression ratio
+    if (!checkFinalCompressionRatio(fo))
+        throwNotCompressible();
 }
 
 
diff --git a/src/packer.cpp b/src/packer.cpp
index 293a3860..12f2ab78 100644
--- a/src/packer.cpp
+++ b/src/packer.cpp
@@ -260,9 +260,9 @@ bool Packer::checkCompressionRatio(unsigned u_len, unsigned c_len) const
     //assert((off_t)u_len < file_size);
 
 #if 1
-    if (c_len >= u_len - u_len / 8)         // min. 12.5% gain
+    if (c_len + 512 >= u_len)           // min. 512 bytes gain
         return false;
-    if (c_len + 512 >= u_len)               // min. 512 bytes gain
+    if (c_len >= u_len - u_len / 8)     // min. 12.5% gain
         return false;
 #else
     if (c_len >= u_len)
@@ -272,6 +272,21 @@ bool Packer::checkCompressionRatio(unsigned u_len, unsigned c_len) const
 }
 
 
+bool Packer::checkFinalCompressionRatio(const OutputFile *fo) const
+{
+    unsigned u_len = file_size;
+    unsigned c_len = fo->getBytesWritten();
+
+    assert((int)u_len > 0);
+    assert((int)c_len > 0);
+
+    if (c_len + 4096 <= u_len)          // ok if we have 4096 bytes gain
+        return true;
+
+    return checkCompressionRatio(u_len, c_len);
+}
+
+
 /*************************************************************************
 //
 **************************************************************************/
@@ -350,7 +365,7 @@ void Packer::verifyOverlappingDecompression(MemBuffer *buf,
     //   buf was allocated with MemBuffer.allocForCompression(), and
     //   its contents are no longer needed, i.e. the compressed data
     //   must have been already written.
-    //   We now could performa a real overlapping decompression and
+    //   We now could perform a real overlapping decompression and
     //   verify the checksum.
     //
     // Note:
diff --git a/src/packer.h b/src/packer.h
index 0a03e600..69f116e0 100644
--- a/src/packer.h
+++ b/src/packer.h
@@ -156,6 +156,7 @@ protected:
     virtual void decompress(const upx_bytep in,
                             upx_bytep out, bool verify_checksum=true);
     virtual bool checkCompressionRatio(unsigned u_len, unsigned c_len) const;
+    virtual bool checkFinalCompressionRatio(const OutputFile *fo) const;
 
     // high-level compression drivers
     void compressWithFilters(Filter *ft, unsigned *overlapoh,