Don't prepend 'fmap.' to section names. It will break the Cr-48 installer.

utility/dump_fmap.c

 /*
  * Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 39 matching lines @@
       char* s;
       for (s=buf;* s; s++)
         if (*s == ' ')
          *s = '_';
       FILE* fp = fopen(buf,"wb");
       if (!fp) {
         fprintf(stderr, "%s: can't open %s: %s\n",
                 progname, buf, strerror(errno));
         retval = 1;
       } else {
-        if (1 != fwrite(base_of_rom + ah->area_offset, ah->area_size, 1, fp)) {
+        if (ah->area_size &&
+            1 != fwrite(base_of_rom + ah->area_offset, ah->area_size, 1, fp)) {
           fprintf(stderr, "%s: can't write %s: %s\n",
                   progname, buf, strerror(errno));
           retval = 1;
         } else {
           printf("saved as \"%s\"\n", buf);
         }
         fclose(fp);
       }
     }
 
@@ skipping 88 matching lines @@
   if (0 != munmap(base_of_rom, sb.st_size)) {
     fprintf(stderr, "%s: can't munmap %s: %s\n",
             progname,
             argv[optind],
             strerror(errno));
     return 1;
   }
 
   return retval;
 }