diff --git a/asmrun/natdynlink.c b/asmrun/natdynlink.c
index 3e1a47fb3..4284fee92 100644
--- a/asmrun/natdynlink.c
+++ b/asmrun/natdynlink.c
@@ -79,7 +79,7 @@ CAMLprim value caml_natdynlink_run(void *handle, value symbol) {
   CAMLparam1 (symbol);
   CAMLlocal1 (result);
   void *sym,*sym2;
-  struct code_fragment * cf;
+  struct code_fragment * cf = NULL;
 
 #define optsym(n) getsym(handle,unit,n)
   char *unit;
@@ -93,11 +93,6 @@ CAMLprim value caml_natdynlink_run(void *handle, value symbol) {
   sym = optsym("__gc_roots");
   if (NULL != sym) caml_register_dyn_global(sym);
 
-  sym = optsym("__data_begin");
-  sym2 = optsym("__data_end");
-  if (NULL != sym && NULL != sym2)
-    caml_page_table_add(In_static_data, sym, sym2);
-
   sym = optsym("__code_begin");
   sym2 = optsym("__code_end");
   if (NULL != sym && NULL != sym2) {
@@ -105,10 +100,23 @@ CAMLprim value caml_natdynlink_run(void *handle, value symbol) {
     cf = caml_stat_alloc(sizeof(struct code_fragment));
     cf->code_start = (char *) sym;
     cf->code_end = (char *) sym2;
+    cf->data_start = NULL;
+    cf->data_end = NULL;
     cf->digest_computed = 0;
-    caml_ext_table_add(&caml_code_fragments_table, cf);
   }
 
+  sym = optsym("__data_begin");
+  sym2 = optsym("__data_end");
+  if (NULL != sym && NULL != sym2) {
+    caml_page_table_add(In_static_data, sym, sym2);
+    if (cf != NULL) {
+      cf->data_start = (char *) sym;
+      cf->data_end = (char *) sym2;
+    }
+  }
+
+  if (cf != NULL) caml_ext_table_add(&caml_code_fragments_table, cf);
+
   entrypoint = optsym("__entry");
   if (NULL != entrypoint) result = caml_callback((value)(&entrypoint), 0);
   else result = Val_unit;
diff --git a/asmrun/startup.c b/asmrun/startup.c
index 5cbd42cff..dd46b20de 100644
--- a/asmrun/startup.c
+++ b/asmrun/startup.c
@@ -52,6 +52,22 @@ static void init_static(void)
 
   caml_init_atom_table ();
 
+  /* Register the data in the table of code fragments */
+  cf = caml_stat_alloc(sizeof(struct code_fragment));
+  if (caml_data_segments[0].begin != 0) {
+    cf->data_start = caml_data_segments[0].begin;
+    cf->data_end = caml_data_segments[0].end;
+    for (i = 1; caml_data_segments[i].begin != 0; i ++) {
+      if (caml_data_segments[i].begin < cf->data_start)
+        cf->data_start = caml_data_segments[i].begin;
+      if (caml_data_segments[i].end > cf->data_end)
+        cf->data_end = caml_data_segments[i].end;
+    }
+  } else {
+    cf->data_start = NULL;
+    cf->data_end = NULL;
+  }
+
   for (i = 0; caml_data_segments[i].begin != 0; i++) {
     /* PR#5509: we must include the zero word at end of data segment,
        because pointers equal to caml_data_segments[i].end are static data. */
@@ -70,7 +86,6 @@ static void init_static(void)
       caml_code_area_end = caml_code_segments[i].end;
   }
   /* Register the code in the table of code fragments */
-  cf = caml_stat_alloc(sizeof(struct code_fragment));
   cf->code_start = caml_code_area_start;
   cf->code_end = caml_code_area_end;
   cf->digest_computed = 0;
diff --git a/byterun/caml/fix_code.h b/byterun/caml/fix_code.h
index c63989452..82f4507bd 100644
--- a/byterun/caml/fix_code.h
+++ b/byterun/caml/fix_code.h
@@ -21,6 +21,8 @@
 #include "misc.h"
 #include "mlvalues.h"
 
+extern char *caml_data;
+extern asize_t caml_data_size;
 extern code_t caml_start_code;
 extern asize_t caml_code_size;
 extern unsigned char * caml_saved_code;
diff --git a/byterun/caml/intext.h b/byterun/caml/intext.h
index b72d802ac..1b6ddcb6e 100644
--- a/byterun/caml/intext.h
+++ b/byterun/caml/intext.h
@@ -177,12 +177,18 @@ CAMLextern void caml_deserialize_error(char * msg);
 struct code_fragment {
   char * code_start;
   char * code_end;
+  char * data_start;
+  char * data_end;
   unsigned char digest[16];
   char digest_computed;
 };
 
 struct ext_table caml_code_fragments_table;
 
+/* Defined in misc.c */
+
+CAMLextern void caml_update_code_fragment_digest(struct code_fragment *cf);
+
 /* </private> */
 
 #ifdef __cplusplus
diff --git a/byterun/extern.c b/byterun/extern.c
index 8bdaf3090..b77cd5935 100644
--- a/byterun/extern.c
+++ b/byterun/extern.c
@@ -22,7 +22,6 @@
 #include "caml/gc.h"
 #include "caml/intext.h"
 #include "caml/io.h"
-#include "caml/md5.h"
 #include "caml/memory.h"
 #include "caml/misc.h"
 #include "caml/mlvalues.h"
@@ -895,10 +894,7 @@ static struct code_fragment * extern_find_code(char *addr)
   int i;
   for (i = caml_code_fragments_table.size - 1; i >= 0; i--) {
     struct code_fragment * cf = caml_code_fragments_table.contents[i];
-    if (! cf->digest_computed) {
-      caml_md5_block(cf->digest, cf->code_start, cf->code_end - cf->code_start);
-      cf->digest_computed = 1;
-    }
+    if (! cf->digest_computed) caml_update_code_fragment_digest(cf);
     if (cf->code_start <= addr && addr < cf->code_end) return cf;
   }
   return NULL;
diff --git a/byterun/fix_code.c b/byterun/fix_code.c
index 0d7c8cbaf..b22f82997 100644
--- a/byterun/fix_code.c
+++ b/byterun/fix_code.c
@@ -23,12 +23,13 @@
 #include "caml/fix_code.h"
 #include "caml/instruct.h"
 #include "caml/intext.h"
-#include "caml/md5.h"
 #include "caml/memory.h"
 #include "caml/misc.h"
 #include "caml/mlvalues.h"
 #include "caml/reverse.h"
 
+char *caml_data;
+asize_t caml_data_size;
 code_t caml_start_code;
 asize_t caml_code_size;
 unsigned char * caml_saved_code;
@@ -41,8 +42,9 @@ void caml_init_code_fragments(void) {
   cf = caml_stat_alloc(sizeof(struct code_fragment));
   cf->code_start = (char *) caml_start_code;
   cf->code_end = (char *) caml_start_code + caml_code_size;
-  caml_md5_block(cf->digest, caml_start_code, caml_code_size);
-  cf->digest_computed = 1;
+  cf->data_start = (char *) caml_data;
+  cf->data_end = (char *) caml_data + caml_data_size;
+  caml_update_code_fragment_digest(cf);
   caml_ext_table_init(&caml_code_fragments_table, 8);
   caml_ext_table_add(&caml_code_fragments_table, cf);
 }
diff --git a/byterun/intern.c b/byterun/intern.c
index 23eaebce5..313ca5ec5 100644
--- a/byterun/intern.c
+++ b/byterun/intern.c
@@ -24,7 +24,6 @@
 #include "caml/gc.h"
 #include "caml/intext.h"
 #include "caml/io.h"
-#include "caml/md5.h"
 #include "caml/memory.h"
 #include "caml/mlvalues.h"
 #include "caml/misc.h"
@@ -855,10 +854,7 @@ static char * intern_resolve_code_pointer(unsigned char digest[16],
   int i;
   for (i = caml_code_fragments_table.size - 1; i >= 0; i--) {
     struct code_fragment * cf = caml_code_fragments_table.contents[i];
-    if (! cf->digest_computed) {
-      caml_md5_block(cf->digest, cf->code_start, cf->code_end - cf->code_start);
-      cf->digest_computed = 1;
-    }
+    if (! cf->digest_computed) caml_update_code_fragment_digest(cf);
     if (memcmp(digest, cf->digest, 16) == 0) {
       if (cf->code_start + offset < cf->code_end)
         return cf->code_start + offset;
diff --git a/byterun/meta.c b/byterun/meta.c
index 0e0864a3a..4298d7b6e 100644
--- a/byterun/meta.c
+++ b/byterun/meta.c
@@ -52,6 +52,8 @@ CAMLprim value caml_reify_bytecode(value prog, value len)
 
   cf->code_start = (char *) prog;
   cf->code_end = (char *) prog + Long_val(len);
+  cf->data_start = NULL;
+  cf->data_end = NULL;
   cf->digest_computed = 0;
   caml_ext_table_add(&caml_code_fragments_table, cf);
 
diff --git a/byterun/misc.c b/byterun/misc.c
index 8191b83e7..a30cece3b 100644
--- a/byterun/misc.c
+++ b/byterun/misc.c
@@ -15,8 +15,10 @@
 #include <string.h>
 #include <stdarg.h>
 #include "caml/config.h"
+#include "caml/intext.h"
 #include "caml/misc.h"
 #include "caml/memory.h"
+#include "caml/md5.h"
 
 caml_timing_hook caml_major_slice_begin_hook = NULL;
 caml_timing_hook caml_major_slice_end_hook = NULL;
@@ -144,6 +146,17 @@ void caml_ext_table_free(struct ext_table * tbl, int free_entries)
   caml_stat_free(tbl->contents);
 }
 
+void caml_update_code_fragment_digest(struct code_fragment *cf) {
+  int i;
+  unsigned char code_digest[16];
+  unsigned char data_digest[16];
+  caml_md5_block(code_digest, cf->code_start, cf->code_end - cf->code_start);
+  caml_md5_block(data_digest, cf->data_start, cf->data_end - cf->data_start);
+  for (i = 0 ; i < 16 ; i ++)
+    cf->digest[i] = code_digest[i] ^ data_digest[i];
+  cf->digest_computed = 1;
+}
+
 CAMLexport char * caml_strdup(const char * s)
 {
   size_t slen = strlen(s);
diff --git a/byterun/startup.c b/byterun/startup.c
index faa0e4a1f..b03d24048 100644
--- a/byterun/startup.c
+++ b/byterun/startup.c
@@ -270,7 +270,6 @@ CAMLexport void caml_main(char **argv)
 {
   int fd, pos;
   struct exec_trailer trail;
-  struct channel * chan;
   value res;
   char * shared_lib_path, * shared_libs, * req_prims;
   char * exe_name;
@@ -334,6 +333,10 @@ CAMLexport void caml_main(char **argv)
   caml_interprete(NULL, 0);
   /* Initialize the debugger, if needed */
   caml_debugger_init();
+  /* Load the globals */
+  caml_data_size = caml_seek_section(fd, &trail, "DATA");
+  caml_data = read_section(fd, &trail, "DATA");
+  caml_global_data = caml_input_value_from_block(caml_data, caml_data_size);
   /* Load the code */
   caml_code_size = caml_seek_section(fd, &trail, "CODE");
   caml_load_code(fd, caml_code_size);
@@ -347,11 +350,8 @@ CAMLexport void caml_main(char **argv)
   caml_stat_free(shared_lib_path);
   caml_stat_free(shared_libs);
   caml_stat_free(req_prims);
-  /* Load the globals */
-  caml_seek_section(fd, &trail, "DATA");
-  chan = caml_open_descriptor_in(fd);
-  caml_global_data = caml_input_val(chan);
-  caml_close_channel(chan); /* this also closes fd */
+  /* Close */
+  close(fd);
   caml_stat_free(trail.section);
   /* Ensure that the globals are in the major heap. */
   caml_oldify_one (caml_global_data, &caml_global_data);
@@ -421,6 +421,8 @@ CAMLexport void caml_startup_code(
   /* Load the code */
   caml_start_code = code;
   caml_code_size = code_size;
+  caml_data = data;
+  caml_data_size = data_size;
   caml_init_code_fragments();
   caml_init_debug_info();
   if (caml_debugger_in_use) {
diff --git a/testsuite/tests/lib-marshal-closure/.gitignore b/testsuite/tests/lib-marshal-closure/.gitignore
new file mode 100644
index 000000000..9f2824deb
--- /dev/null
+++ b/testsuite/tests/lib-marshal-closure/.gitignore
@@ -0,0 +1,2 @@
+*.err
+data
diff --git a/testsuite/tests/lib-marshal-closure/Makefile b/testsuite/tests/lib-marshal-closure/Makefile
new file mode 100644
index 000000000..5b5d92b20
--- /dev/null
+++ b/testsuite/tests/lib-marshal-closure/Makefile
@@ -0,0 +1,61 @@
+#########################################################################
+#                                                                       #
+#                                 OCaml                                 #
+#                                                                       #
+#                          Benoit Vaugon, ENSTA                         #
+#                                                                       #
+#   Copyright 2014 Institut National de Recherche en Informatique et    #
+#   en Automatique.  All rights reserved.  This file is distributed     #
+#   under the terms of the Q Public License version 1.0.                #
+#                                                                       #
+#########################################################################
+
+BINARIES := write32.byte write32.native read32.byte read32.native \
+	    write64.byte write64.native read64.byte read64.native
+
+BASEDIR=../..
+
+.PHONY: default
+default:
+	@$(MAKE) compile
+	@$(MAKE) run
+
+.PHONY: compile
+compile: $(BINARIES)
+
+.PHONY: run
+run:
+	@for arch in 32 64; do						\
+	  for kind in byte native; do					\
+	    echo -n " ... testing 'arch-$$arch/$$kind'";		\
+	    rm -f data;                             			\
+	    ./write$$arch.$$kind					\
+	      > write$$arch$$kind.out 2> write$$arch$$kind.err		\
+	      || exit 1;						\
+	    ./read$$arch.$$kind						\
+	      > read$$arch$$kind.out 2> read$$arch$$kind.err		\
+	      && ( echo " => passed" )					\
+	      || ( echo " => failed" )					\
+	  done;								\
+	done
+
+###
+
+.PHONY: promote
+promote: defaultpromote
+
+.PHONY: clean
+clean: defaultclean
+	@rm -f data *.byte *.native *.out *.err
+
+###
+
+%.byte: %.ml
+	@$(OCAMLC) $< -o $@
+
+%.native: %.ml
+	@$(OCAMLOPT) $< -o $@
+
+###
+
+include $(BASEDIR)/makefiles/Makefile.common
diff --git a/testsuite/tests/lib-marshal-closure/read32.ml b/testsuite/tests/lib-marshal-closure/read32.ml
new file mode 100644
index 000000000..fbcdded50
--- /dev/null
+++ b/testsuite/tests/lib-marshal-closure/read32.ml
@@ -0,0 +1,31 @@
+(***********************************************************************)
+(*                                                                     *)
+(*                                OCaml                                *)
+(*                                                                     *)
+(*                         Benoit Vaugon, ENSTA                        *)
+(*                                                                     *)
+(*  Copyright 2014 Institut National de Recherche en Informatique et   *)
+(*  en Automatique.  All rights reserved.  This file is distributed    *)
+(*  under the terms of the Q Public License version 1.0.               *)
+(*                                                                     *)
+(***********************************************************************)
+
+let fname = "data";;
+
+let f () = [ 1; 2; 3; 4 ];;
+
+try
+  let ic = open_in fname in
+  let g : unit -> float list = Marshal.from_channel ic in
+  close_in ic;
+  Printf.printf "%f\n" (List.nth (g ()) 0);
+with
+| Sys_error _ ->
+  Printf.printf "Do not import %S, ok\n" fname;
+| Failure msg when String.sub msg 0 32 = "input_value: unknown code module" ->
+  Printf.printf "Incompatible closure, ok\n";
+;;
+
+let oc = open_out fname in
+Marshal.to_channel oc f [ Marshal.Closures ];
+close_out oc;;
diff --git a/testsuite/tests/lib-marshal-closure/read64.ml b/testsuite/tests/lib-marshal-closure/read64.ml
new file mode 100644
index 000000000..5501a01ee
--- /dev/null
+++ b/testsuite/tests/lib-marshal-closure/read64.ml
@@ -0,0 +1,31 @@
+(***********************************************************************)
+(*                                                                     *)
+(*                                OCaml                                *)
+(*                                                                     *)
+(*                         Benoit Vaugon, ENSTA                        *)
+(*                                                                     *)
+(*  Copyright 2014 Institut National de Recherche en Informatique et   *)
+(*  en Automatique.  All rights reserved.  This file is distributed    *)
+(*  under the terms of the Q Public License version 1.0.               *)
+(*                                                                     *)
+(***********************************************************************)
+
+let fname = "data";;
+
+let f () = [ 1; 2; 3; 4; 5 ];;
+
+try
+  let ic = open_in fname in
+  let g : unit -> float list = Marshal.from_channel ic in
+  close_in ic;
+  Printf.printf "%f\n" (List.nth (g ()) 0);
+with
+| Sys_error _ ->
+  Printf.printf "Do not import %S, ok\n" fname;
+| Failure msg when String.sub msg 0 32 = "input_value: unknown code module" ->
+  Printf.printf "Incompatible closure, ok\n";
+;;
+
+let oc = open_out fname in
+Marshal.to_channel oc f [ Marshal.Closures ];
+close_out oc;;
diff --git a/testsuite/tests/lib-marshal-closure/write32.ml b/testsuite/tests/lib-marshal-closure/write32.ml
new file mode 100644
index 000000000..8140bc1d2
--- /dev/null
+++ b/testsuite/tests/lib-marshal-closure/write32.ml
@@ -0,0 +1,31 @@
+(***********************************************************************)
+(*                                                                     *)
+(*                                OCaml                                *)
+(*                                                                     *)
+(*                         Benoit Vaugon, ENSTA                        *)
+(*                                                                     *)
+(*  Copyright 2014 Institut National de Recherche en Informatique et   *)
+(*  en Automatique.  All rights reserved.  This file is distributed    *)
+(*  under the terms of the Q Public License version 1.0.               *)
+(*                                                                     *)
+(***********************************************************************)
+
+let fname = "data";;
+
+let f () = [ 3.14; 6.28 ];;
+
+try
+  let ic = open_in fname in
+  let g : unit -> float list = Marshal.from_channel ic in
+  close_in ic;
+  Printf.printf "%f\n" (List.nth (g ()) 0);
+with
+| Sys_error _ ->
+  Printf.printf "Do not import %S, ok\n" fname;
+| Failure msg when String.sub msg 0 32 = "input_value: unknown code module" ->
+  Printf.printf "Incompatible closure, ok\n";
+;;
+
+let oc = open_out fname in
+Marshal.to_channel oc f [ Marshal.Closures ];
+close_out oc;;
diff --git a/testsuite/tests/lib-marshal-closure/write64.ml b/testsuite/tests/lib-marshal-closure/write64.ml
new file mode 100644
index 000000000..fab080a2b
--- /dev/null
+++ b/testsuite/tests/lib-marshal-closure/write64.ml
@@ -0,0 +1,31 @@
+(***********************************************************************)
+(*                                                                     *)
+(*                                OCaml                                *)
+(*                                                                     *)
+(*                         Benoit Vaugon, ENSTA                        *)
+(*                                                                     *)
+(*  Copyright 2014 Institut National de Recherche en Informatique et   *)
+(*  en Automatique.  All rights reserved.  This file is distributed    *)
+(*  under the terms of the Q Public License version 1.0.               *)
+(*                                                                     *)
+(***********************************************************************)
+
+let fname = "data";;
+
+let f () = [ 3.14; 6.28; 9.42 ];;
+
+try
+  let ic = open_in fname in
+  let g : unit -> float list = Marshal.from_channel ic in
+  close_in ic;
+  Printf.printf "%f\n" (List.nth (g ()) 0);
+with
+| Sys_error _ ->
+  Printf.printf "Do not import %S, ok\n" fname;
+| Failure msg when String.sub msg 0 32 = "input_value: unknown code module" ->
+  Printf.printf "Incompatible closure, ok\n";
+;;
+
+let oc = open_out fname in
+Marshal.to_channel oc f [ Marshal.Closures ];
+close_out oc;;