diff --git a/BUGS b/BUGS
index 68ef302..fa5cbf3 100644
--- a/BUGS
+++ b/BUGS
@@ -1,5 +1,10 @@
-BUGME November 2010
+BUGME February 2011
 
-Fails on mac osx : needs unnamed semaphores converted to named to work. Last
-working version 0.530.
+Mac OSX does not use multithreading, silently ignoring it so as to work. It
+does not support unnamed semaphores so another synchronisation primitive will
+be required (named semaphores or other).
 
+There have been rare reports of corruption on decompression of files >20GB.
+The cause remains unknown so caution is recommended, and not to use lrzip for
+mission critical massive file backups. Checking files with md5sum is
+recommended till further notice.
diff --git a/ChangeLog b/ChangeLog
index 242d75c..30344e7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,18 @@
 lrzip ChangeLog
+FEBRUARY 2011, version 0.552 Con Kolivas
+* Fix incompressible blocks causing failure with bzip2 and gzip.
+* Freebsd doesn't do mremap, use the fake one.
+* Update copyright notices.
+* Flush writes to disk before allocating ram.
+* Relax memory allocation when no back end compression will be used.
+* Clean up unnecessary semaphore usage in decompression.
+* Fix minor typos.
+* Convert mmaps to malloc in runzip as they may silently fail if not a
+multiple of page size, thereby leading to silent corruption on decompression.
+* Return the correct length by unzip_literal.
+* Use wrappers to serialise threads on OSX and bypass use of unnamed semaphores
+which aren't supported.
+
 DECEMBER 2010, version 0.551 Con Kolivas
 * Fix stdin failing due to getting sizes all wrong.
 * Fix stdin compression values not being shown at end.
diff --git a/WHATS-NEW b/WHATS-NEW
index 09a561d..c15eb17 100644
--- a/WHATS-NEW
+++ b/WHATS-NEW
@@ -1,3 +1,11 @@
+lrzip-0.552
+
+Fixed a potential silent corruption bug on decompression.
+Fixed compilation on freebsd.
+Fixed failures on incompressible blocks with bzip2 or gzip.
+Fixed osx failing to work. It does not support threaded compression or
+decompression but should work again.
+
 lrzip-0.551
 
 Compressing from stdin should be unbroken again.
diff --git a/configure b/configure
index 47bfc2c..eb19ed6 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.67 for lrzip 0.551.
+# Generated by GNU Autoconf 2.67 for lrzip 0.552.
 #
 # Report bugs to <kernel@kolivas.org>.
 #
@@ -551,9 +551,9 @@ MAKEFLAGS=
 
 # Identity of this package.
 PACKAGE_NAME='lrzip'
-PACKAGE_TARNAME='lrzip-0.551'
-PACKAGE_VERSION='0.551'
-PACKAGE_STRING='lrzip 0.551'
+PACKAGE_TARNAME='lrzip-0.552'
+PACKAGE_VERSION='0.552'
+PACKAGE_STRING='lrzip 0.552'
 PACKAGE_BUGREPORT='kernel@kolivas.org'
 PACKAGE_URL=''
 
@@ -1221,7 +1221,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures lrzip 0.551 to adapt to many kinds of systems.
+\`configure' configures lrzip 0.552 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1269,7 +1269,7 @@ Fine tuning of the installation directories:
   --infodir=DIR           info documentation [DATAROOTDIR/info]
   --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]
   --mandir=DIR            man documentation [DATAROOTDIR/man]
-  --docdir=DIR            documentation root [DATAROOTDIR/doc/lrzip-0.551]
+  --docdir=DIR            documentation root [DATAROOTDIR/doc/lrzip-0.552]
   --htmldir=DIR           html documentation [DOCDIR]
   --dvidir=DIR            dvi documentation [DOCDIR]
   --pdfdir=DIR            pdf documentation [DOCDIR]
@@ -1286,7 +1286,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of lrzip 0.551:";;
+     short | recursive ) echo "Configuration of lrzip 0.552:";;
    esac
   cat <<\_ACEOF
 
@@ -1375,7 +1375,7 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-lrzip configure 0.551
+lrzip configure 0.552
 generated by GNU Autoconf 2.67
 
 Copyright (C) 2010 Free Software Foundation, Inc.
@@ -2014,7 +2014,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by lrzip $as_me 0.551, which was
+It was created by lrzip $as_me 0.552, which was
 generated by GNU Autoconf 2.67.  Invocation command line was
 
   $ $0 $@
@@ -5324,7 +5324,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by lrzip $as_me 0.551, which was
+This file was extended by lrzip $as_me 0.552, which was
 generated by GNU Autoconf 2.67.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -5386,7 +5386,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-lrzip config.status 0.551
+lrzip config.status 0.552
 configured by $0, generated by GNU Autoconf 2.67,
   with options \\"\$ac_cs_config\\"
 
diff --git a/configure.ac b/configure.ac
index bd7fbea..53d82d4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-AC_INIT([lrzip],[0.551],[kernel@kolivas.org],[lrzip-0.551])
+AC_INIT([lrzip],[0.552],[kernel@kolivas.org],[lrzip-0.552])
 AC_CONFIG_HEADER(config.h)
 # see what our system is!
 AC_CANONICAL_HOST
diff --git a/man/lrzip.1 b/man/lrzip.1
index 472afe8..257c015 100644
--- a/man/lrzip.1
+++ b/man/lrzip.1
@@ -1,4 +1,4 @@
-.TH "lrzip" "1" "November 2010" "" ""
+.TH "lrzip" "1" "February 2011" "" ""
 .SH "NAME"
 lrzip \- a large-file compression program
 .SH "SYNOPSIS"
@@ -262,7 +262,8 @@ with increasing ram sizes.
 .PP
 .SH "BUGS"
 .PP
-Nil known. Probably lots.
+Rare reports of corruption on decompression of archives larger than 20GB.
+Checking the output always with md5sum or equivalent is suggested.
 
 .PP
 .SH "SEE ALSO"
diff --git a/rzip.h b/rzip.h
index 68ff625..de4046d 100644
--- a/rzip.h
+++ b/rzip.h
@@ -18,7 +18,7 @@
 
 #define LRZIP_MAJOR_VERSION 0
 #define LRZIP_MINOR_VERSION 5
-#define LRZIP_MINOR_SUBVERSION 51
+#define LRZIP_MINOR_SUBVERSION 52
 
 #define NUM_STREAMS 2
 #define STREAM_BUFSIZE (1024 * 1024 * 10)