diff -Nru libzstd-1.4.8+dfsg/debian/changelog libzstd-1.4.8+dfsg/debian/changelog
--- libzstd-1.4.8+dfsg/debian/changelog	2021-10-06 07:27:47.000000000 +0000
+++ libzstd-1.4.8+dfsg/debian/changelog	2021-10-11 18:43:18.000000000 +0000
@@ -1,3 +1,10 @@
+libzstd (1.4.8+dfsg-3+rpi1) bookworm-staging; urgency=medium
+
+  [changes brought forward from 1.4.8+dfsg-2.1+rpi1 by Peter Michael Green <plugwash@raspbian.org> at Fri, 07 May 2021 07:36:26 +0000]
+  * Fix broken unaligned accesses.
+
+ -- Raspbian forward porter <root@raspbian.org>  Mon, 11 Oct 2021 18:43:18 +0000
+
 libzstd (1.4.8+dfsg-3) unstable; urgency=medium
 
   * Team upload.
diff -Nru libzstd-1.4.8+dfsg/debian/patches/9999-fix-broken-memory-access.patch libzstd-1.4.8+dfsg/debian/patches/9999-fix-broken-memory-access.patch
--- libzstd-1.4.8+dfsg/debian/patches/9999-fix-broken-memory-access.patch	1970-01-01 00:00:00.000000000 +0000
+++ libzstd-1.4.8+dfsg/debian/patches/9999-fix-broken-memory-access.patch	2021-10-11 18:43:18.000000000 +0000
@@ -0,0 +1,95 @@
+Description: don't use broken unaligned access
+ Some unaligned accesses are ok on armv6+ but many are not, so violating
+ C's memory alignment rules is dangerous on this architecture, change
+ the defines so the code doesn't do it.
+Author: Peter Micheal Green <plugwash@raspbian.org>
+Last-Update: 2021-05-07
+
+--- libzstd-1.4.8+dfsg.orig/lib/common/mem.h
++++ libzstd-1.4.8+dfsg/lib/common/mem.h
+@@ -144,7 +144,7 @@ MEM_STATIC size_t MEM_swapST(size_t in);
+  */
+ #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define MEM_FORCE_MEMORY_ACCESS 2
++#    define MEM_FORCE_MEMORY_ACCESS 0
+ #  elif defined(__INTEL_COMPILER) || defined(__GNUC__) || defined(__ICCARM__)
+ #    define MEM_FORCE_MEMORY_ACCESS 1
+ #  endif
+--- libzstd-1.4.8+dfsg.orig/lib/common/xxhash.c
++++ libzstd-1.4.8+dfsg/lib/common/xxhash.c
+@@ -31,7 +31,7 @@
+  */
+ #ifndef XXH_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define XXH_FORCE_MEMORY_ACCESS 2
++#    define XXH_FORCE_MEMORY_ACCESS 0
+ #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) )) || \
+   defined(__ICCARM__)
+--- libzstd-1.4.8+dfsg.orig/lib/legacy/zstd_v02.c
++++ libzstd-1.4.8+dfsg/lib/legacy/zstd_v02.c
+@@ -130,7 +130,7 @@ extern "C" {
+  */
+ #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define MEM_FORCE_MEMORY_ACCESS 2
++#    define MEM_FORCE_MEMORY_ACCESS 0
+ #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
+ #    define MEM_FORCE_MEMORY_ACCESS 1
+--- libzstd-1.4.8+dfsg.orig/lib/legacy/zstd_v03.c
++++ libzstd-1.4.8+dfsg/lib/legacy/zstd_v03.c
+@@ -131,7 +131,7 @@ extern "C" {
+  */
+ #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define MEM_FORCE_MEMORY_ACCESS 2
++#    define MEM_FORCE_MEMORY_ACCESS 0
+ #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
+ #    define MEM_FORCE_MEMORY_ACCESS 1
+--- libzstd-1.4.8+dfsg.orig/lib/legacy/zstd_v04.c
++++ libzstd-1.4.8+dfsg/lib/legacy/zstd_v04.c
+@@ -102,7 +102,7 @@ extern "C" {
+  */
+ #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define MEM_FORCE_MEMORY_ACCESS 2
++#    define MEM_FORCE_MEMORY_ACCESS 0
+ #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
+ #    define MEM_FORCE_MEMORY_ACCESS 1
+--- libzstd-1.4.8+dfsg.orig/lib/legacy/zstd_v05.c
++++ libzstd-1.4.8+dfsg/lib/legacy/zstd_v05.c
+@@ -121,7 +121,7 @@ extern "C" {
+  */
+ #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define MEM_FORCE_MEMORY_ACCESS 2
++#    define MEM_FORCE_MEMORY_ACCESS 0
+ #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
+ #    define MEM_FORCE_MEMORY_ACCESS 1
+--- libzstd-1.4.8+dfsg.orig/lib/legacy/zstd_v06.c
++++ libzstd-1.4.8+dfsg/lib/legacy/zstd_v06.c
+@@ -123,7 +123,7 @@ extern "C" {
+  */
+ #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define MEM_FORCE_MEMORY_ACCESS 2
++#    define MEM_FORCE_MEMORY_ACCESS 0
+ #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
+ #    define MEM_FORCE_MEMORY_ACCESS 1
+--- libzstd-1.4.8+dfsg.orig/lib/legacy/zstd_v07.c
++++ libzstd-1.4.8+dfsg/lib/legacy/zstd_v07.c
+@@ -283,7 +283,7 @@ extern "C" {
+  */
+ #ifndef MEM_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
+ #  if defined(__GNUC__) && ( defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) || defined(__ARM_ARCH_6T2__) )
+-#    define MEM_FORCE_MEMORY_ACCESS 2
++#    define MEM_FORCE_MEMORY_ACCESS 0
+ #  elif (defined(__INTEL_COMPILER) && !defined(WIN32)) || \
+   (defined(__GNUC__) && ( defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__) ))
+ #    define MEM_FORCE_MEMORY_ACCESS 1
diff -Nru libzstd-1.4.8+dfsg/debian/patches/series libzstd-1.4.8+dfsg/debian/patches/series
--- libzstd-1.4.8+dfsg/debian/patches/series	2021-10-06 07:27:47.000000000 +0000
+++ libzstd-1.4.8+dfsg/debian/patches/series	2021-10-11 18:43:18.000000000 +0000
@@ -5,3 +5,4 @@
 0015-Skip-dev-random-tests-on-hurd.patch
 0017-alpha-fbfs-st_mtime.patch
 0018-fix-file-permissions-on-compression.patch
+9999-fix-broken-memory-access.patch