diff --git a/libisofs/libisofs.h b/libisofs/libisofs.h
index d2be2de..564f091 100644
--- a/libisofs/libisofs.h
+++ b/libisofs/libisofs.h
@@ -1935,14 +1935,16 @@ void el_torito_patch_isolinux_image(ElToritoBootImage *bootimg);
  *        bitmask style flag. The following values are defined:
  *
  *        bit 0 -> 1 to path the image, 0 to not
- *                 Patching the image involves the writting of a 56 bytes
+ *                 Patching the image involves the writing of a 56 bytes
  *                 boot information table at offset 8 of the boot image file.
- *                 The original boot image file won't be modified. This is needed
- *                 to allow isolinux images to be bootable.
- *        bit 1 -> 1 to generate an hybrid image, 0 to not
- *                 An hybrid image is a boot image that boots from either CD/DVD
- *                 media or from USB sticks. For that, you should use an isolinux
- *                 image that supports hybrid mode. Recent images support this.
+ *                 The original boot image file will not be modified. This is
+ *                 needed to allow isolinux images to be bootable.
+ *        bit 1 -> 1 to generate an hybrid image with MBR, 0 to not
+ *                 An hybrid image is a boot image that boots from either
+ *                 CD/DVD media or from disk-like media, e.g. USB stick.
+ *                 For that you need isolinux.bin from SYSLINUX 3.72 or later.
+ *                 IMPORTANT: The application has to take care that the image
+ *                            on media gets padded up to the next full MB.
  * @param flag
  *        Reserved for future usage, set to 0.
  * @return
diff --git a/libisofs/system_area.c b/libisofs/system_area.c
index 503a066..b96f472 100644
--- a/libisofs/system_area.c
+++ b/libisofs/system_area.c
@@ -48,7 +48,13 @@ int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
         img_blocks = t->curblock;
         ret = make_isohybrid_mbr(t->bootimg->sections[0].block, &img_blocks, (char*)buf, 0);
 
+/* 
+        API description of el_torito_set_isolinux_options() prescribes
+        to pad to full MB.
+        So this is not urgent any more :
+
         // FIXME the new img_blocks size should be taken into account
+*/
 
         if (ret != 1) {
             /* error, it should never happen */