diff --git a/libisofs/fs_image.c b/libisofs/fs_image.c
index cf15ae4..9dc9a6a 100644
--- a/libisofs/fs_image.c
+++ b/libisofs/fs_image.c
@@ -6298,25 +6298,46 @@ int iso_file_get_old_image_sections(IsoFile *file, int *section_count,
 /* Rank two IsoFileSource by their eventual old image LBAs.
    Other IsoFileSource classes will be ranked only roughly.
 */
-int iso_ifs_sections_cmp(IsoFileSource *s1, IsoFileSource *s2, int flag)
+int iso_ifs_sections_cmp(IsoFileSource *s1, IsoFileSource *s2, int *cmp_ret,
+                         int flag)
 {
     int i;
     ImageFileSourceData *d1, *d2;
 
-    if (s1->class != s2->class)
-        return (s1->class < s2->class ? -1 : 1);
-    if (s1->class != &ifs_class)
-        return(0);
-
-    d1= s1->data;
-    d2= s2->data;
-    for (i = 0; i < d1->nsections; i++) {
-        if (i >= d2->nsections)
-            return 1;
-        if (d1->sections[i].block != d2->sections[i].block)
-            return (d1->sections[i].block < d2->sections[i].block ? -1 : 1);
-        if (d1->sections[i].size != d2->sections[i].size)
-            return (d1->sections[i].size < d2->sections[i].size ? -1 : 1);
+    if (s1->class != s2->class) {
+        *cmp_ret = (s1->class < s2->class ? -1 : 1);
+        return 0;
     }
-    return(0);
+    if (s1->class != &ifs_class) {
+        *cmp_ret = 0;
+        return 0;
+    }
+
+    d1 = s1->data;
+    d2 = s2->data;
+    if (d1->nsections < 1)
+        return 0;
+    if (d1->sections[0].size < 1)
+        return 0;
+    for (i = 0; i < d1->nsections; i++) {
+        if (i >= d2->nsections) {
+            *cmp_ret = 1;
+            return 1;
+        }
+        if (d1->sections[i].block != d2->sections[i].block) {
+            *cmp_ret = (d1->sections[i].block < d2->sections[i].block ? -1 : 1);
+            return 1;
+        }
+        if (d1->sections[i].size != d2->sections[i].size) {
+            *cmp_ret = (d1->sections[i].size < d2->sections[i].size ? -1 : 1);
+            return 1;
+        }
+    }
+    if (i < d2->nsections) {
+        *cmp_ret = -1;
+        return 1;
+    }
+    *cmp_ret = 0;
+    return 1;
 }
+
diff --git a/libisofs/fsource.h b/libisofs/fsource.h
index 1640c90..dfb6a45 100644
--- a/libisofs/fsource.h
+++ b/libisofs/fsource.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2007 Vreixo Formoso
- * Copyright (c) 2009 - 2011 Thomas Schmitt
+ * Copyright (c) 2009 - 2015 Thomas Schmitt
  * 
  * This file is part of the libisofs project; you can redistribute it and/or 
  * modify it under the terms of the GNU General Public License version 2 
@@ -34,9 +34,13 @@ int iso_local_filesystem_new(IsoFilesystem **fs);
 
 
 /* Rank two IsoFileSource of ifs_class by their eventual old image LBAs.
-   Other IsoFileSource classes will be ranked only roughly.
+ * @param cmp_ret  will return the reply value -1, 0, or 1.
+ * @return         1= *cmp_ret is a valid reply
+ *                 0= not both streams are of ifs_class,
+ *                    *cmp_ret is only a rough estimation.
 */
-int iso_ifs_sections_cmp(IsoFileSource *s1, IsoFileSource *s2, int flag);
+int iso_ifs_sections_cmp(IsoFileSource *s1, IsoFileSource *s2, int *cmp_ret,
+                         int flag);
 
 
 /* Create an independent copy of an ifs_class IsoFileSource.
diff --git a/libisofs/stream.c b/libisofs/stream.c
index d450393..0bd67ed 100644
--- a/libisofs/stream.c
+++ b/libisofs/stream.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2007 Vreixo Formoso
- * Copyright (c) 2009 - 2011 Thomas Schmitt
+ * Copyright (c) 2009 - 2015 Thomas Schmitt
  *
  * This file is part of the libisofs project; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version 2 
@@ -957,6 +957,23 @@ int iso_stream_set_image_ino(IsoStream *stream, ino_t ino, int flag)
    return 0;
 }
 
+int iso_stream_cmp_ifs_sections(IsoStream *s1, IsoStream *s2, int *cmp_ret,
+                                int flag)
+{   
+    int ret;
+    FSrcStreamData *fssd1, *fssd2;
+
+    if (s1->class != &fsrc_stream_class || s2->class != &fsrc_stream_class)
+        return 0;
+    /* Compare eventual image data section LBA and sizes */
+    fssd1= (FSrcStreamData *) s1->data;
+    fssd2= (FSrcStreamData *) s2->data;
+    ret = iso_ifs_sections_cmp(fssd1->src, fssd2->src, cmp_ret, 0);
+    if (ret <= 0)
+        return 0;
+    return 1;
+}
+
 /* API */ 
 int iso_stream_cmp_ino(IsoStream *s1, IsoStream *s2, int flag)
 {
@@ -965,8 +982,6 @@ int iso_stream_cmp_ino(IsoStream *s1, IsoStream *s2, int flag)
     dev_t dev_id1, dev_id2;
     ino_t ino_id1, ino_id2;
     off_t size1, size2;
-    FSrcStreamData *fssd1, *fssd2;
-
 
 /*
    #define Libisofs_stream_cmp_ino_debuG 1
@@ -983,6 +998,9 @@ int iso_stream_cmp_ino(IsoStream *s1, IsoStream *s2, int flag)
     if (s2 == NULL)
         return 1;
 
+    if (iso_stream_cmp_ifs_sections(s1, s2, &ret, 0) > 0)
+        return ret; /* Both are unfiltered from loaded ISO filesystem */
+
     if (s1->class->version >= 3 && !(flag & 1)) {
        /* Filters may have smarter methods to compare themselves with others */
        ret = s1->class->cmp_ino(s1, s2);
@@ -1042,14 +1060,6 @@ int iso_stream_cmp_ino(IsoStream *s1, IsoStream *s2, int flag)
 
     if (s1->class != s2->class)
         return (s1->class < s2->class ? -1 : 1);
-    if (s1->class == &fsrc_stream_class) {
-        /* Compare eventual image data section LBA and sizes */
-        fssd1= (FSrcStreamData *) s1->data;
-        fssd2= (FSrcStreamData *) s2->data;
-        ret = iso_ifs_sections_cmp(fssd1->src, fssd2->src, 0);
-        if (ret != 0)
-            return ret;
-    }
     if (fs_id1 == 0 && dev_id1 == 0 && ino_id1 == 0) {
         return (s1 < s2 ? -1 : 1);
     }