diff --git a/libisofs/libisofs.h b/libisofs/libisofs.h
index b7aac0a..d3d199c 100644
--- a/libisofs/libisofs.h
+++ b/libisofs/libisofs.h
@@ -3491,8 +3491,10 @@ int el_torito_seems_boot_info_table(ElToritoBootImage *bootimg, int flag);
  *                ElToritoBootImage shall be mentioned.
  *                The first three mentioned GPT partitions get mirrored in the
  *                the partition table of the isohybrid MBR. They get type 0xfe.
- *                Often it is one of these MBR partitions which actually gets
- *                used by EFI.
+ *                The MBR partition entry for PC-BIOS gets type 0x00 rather
+ *                than 0x17.
+ *                Often it is one of the further MBR partitions which actually
+ *                gets used by EFI.
  *                @since 1.2.4
  *        bit8= Mention in isohybrid Apple partition map
  *              APM get written if at least one ElToritoBootImage shall be