--- squashfs-tools/Makefile
+++ squashfs-tools/Makefile
@@ -102,6 +102,8 @@
 # default.  Users can enable xattrs by using the -xattrs option.
 XATTR_DEFAULT = 1
 
+LEGACY_FORMATS_SUPPORT = 1
+
 
 ###############################################
 #        End of BUILD options section         #
@@ -127,6 +129,10 @@
 LINK_STATICALLY_POST:=-Wl,-Bdynamic
 endif
 
+ifeq ($(LEGACY_FORMATS_SUPPORT),1)
+CFLAGS += -DLEGACY_FORMATS_SUPPORT
+endif
+
 LIBS = -lpthread -lm
 ifeq ($(GZIP_SUPPORT),1)
 CFLAGS += -DGZIP_SUPPORT
--- squashfs-tools/unsquash-1.c
+++ squashfs-tools/unsquash-1.c
@@ -22,6 +22,8 @@
  * unsquash-1.c
  */
 
+#ifdef LEGACY_FORMATS_SUPPORT
+
 #include "unsquashfs.h"
 #include "squashfs_compat.h"
 
@@ -355,3 +357,5 @@
 
 	return TRUE;
 }
+
+#endif
--- squashfs-tools/unsquash-2.c
+++ squashfs-tools/unsquash-2.c
@@ -25,7 +25,9 @@
 #include "unsquashfs.h"
 #include "squashfs_compat.h"
 
+#ifdef LEGACY_FORMATS_SUPPORT
 static squashfs_fragment_entry_2 *fragment_table;
+#endif
 
 void read_block_list_2(unsigned int *block_list, char *block_ptr, int blocks)
 {
@@ -40,6 +42,7 @@
 }
 
 
+#ifdef LEGACY_FORMATS_SUPPORT
 int read_fragment_table_2(long long *directory_table_end)
 {
 	int res, i;
@@ -268,3 +271,5 @@
 	}
 	return &i;
 }
+
+#endif
--- squashfs-tools/unsquash-3.c
+++ squashfs-tools/unsquash-3.c
@@ -22,6 +22,8 @@
  * unsquash-3.c
  */
 
+#ifdef LEGACY_FORMATS_SUPPORT
+
 #include "unsquashfs.h"
 #include "squashfs_compat.h"
 
@@ -391,3 +393,5 @@
 	free(dir);
 	return NULL;
 }
+
+#endif
--- squashfs-tools/unsquashfs.c
+++ squashfs-tools/unsquashfs.c
@@ -1771,7 +1771,9 @@
 
 int read_super(char *source)
 {
+#ifdef LEGACY_FORMATS_SUPPORT
 	squashfs_super_block_3 sBlk_3;
+#endif
 	struct squashfs_super_block sBlk_4;
 
 	/*
@@ -1812,6 +1814,7 @@
 		return TRUE;
 	}
 
+#ifdef LEGACY_FORMATS_SUPPORT
 	/*
  	 * Not a Squashfs 4 superblock, try to read a squashfs 3 superblock
  	 * (compatible with 1 and 2 filesystems)
@@ -1907,6 +1910,10 @@
 
 failed_mount:
 	return FALSE;
+#else /* !LEGACY_FORMATS_SUPPORT */
+	ERROR("Filesystem on %s is (%d:%d), which is not supported by this version of unsquashfs!\n", source, sBlk_4.s_major, sBlk_4.s_minor);
+	return FALSE;
+#endif
 }