diff -Nru libcrypto++-8.6.0/debian/changelog libcrypto++-8.6.0/debian/changelog
--- libcrypto++-8.6.0/debian/changelog	2021-09-25 17:44:37.000000000 +0000
+++ libcrypto++-8.6.0/debian/changelog	2021-12-16 18:25:31.000000000 +0000
@@ -1,3 +1,14 @@
+libcrypto++ (8.6.0-2+rpi1) bookworm-staging; urgency=medium
+
+  * Upload to raspbian despite detection of armv7 contaimination,
+    investigation of the code shows that the armv7/neon code seems
+    to be safely behind runtime CPU testection.
+  * Pass -march=armv7+fp instead of -march=armv7 when building "armv4"
+    assembler files. Despite the names these files only seem to be used
+    on armv7.
+
+ -- Peter Michael Green <plugwash@raspbian.org>  Thu, 16 Dec 2021 18:25:31 +0000
+
 libcrypto++ (8.6.0-2) unstable; urgency=medium
 
   * Fix armel and armhf link breakage.
diff -Nru libcrypto++-8.6.0/debian/patches/series libcrypto++-8.6.0/debian/patches/series
--- libcrypto++-8.6.0/debian/patches/series	2021-09-25 17:38:20.000000000 +0000
+++ libcrypto++-8.6.0/debian/patches/series	2021-12-16 18:25:31.000000000 +0000
@@ -1 +1,2 @@
 fix_library_name.patch
+use-fp-with-march.patch
diff -Nru libcrypto++-8.6.0/debian/patches/use-fp-with-march.patch libcrypto++-8.6.0/debian/patches/use-fp-with-march.patch
--- libcrypto++-8.6.0/debian/patches/use-fp-with-march.patch	1970-01-01 00:00:00.000000000 +0000
+++ libcrypto++-8.6.0/debian/patches/use-fp-with-march.patch	2021-12-16 18:25:31.000000000 +0000
@@ -0,0 +1,33 @@
+Description:  pass -march=armv7+fp when building "armv4" assembler files.
+ despite the names these only seem to be used for armv7, and contain
+ neon implementations which won't be built if no -march is specified
+Author: Peter Michael Green <plugwash@raspbian.org>
+
+--- libcrypto++-8.6.0.orig/GNUmakefile
++++ libcrypto++-8.6.0/GNUmakefile
+@@ -1174,11 +1174,11 @@ endif
+ # Also see https://www.cryptopp.com/wiki/Cryptogams.
+ ifeq ($(IS_ARM32)$(IS_LINUX),11)
+   ifeq ($(CLANG_COMPILER),1)
+-    CRYPTOGAMS_ARMV4_FLAG = -march=armv7-a -Wa,--noexecstack
+-    CRYPTOGAMS_ARMV4_THUMB_FLAG = -march=armv7-a -mthumb -Wa,--noexecstack
++    CRYPTOGAMS_ARMV4_FLAG = -march=armv7-a+fp -Wa,--noexecstack
++    CRYPTOGAMS_ARMV4_THUMB_FLAG = -mthumb -Wa,--noexecstack
+   else
+-    CRYPTOGAMS_ARMV4_FLAG = -march=armv7-a -Wa,--noexecstack
+-    CRYPTOGAMS_ARMV4_THUMB_FLAG = -march=armv7-a -Wa,--noexecstack
++    CRYPTOGAMS_ARMV4_FLAG = -march=armv7-a+fp -Wa,--noexecstack
++    CRYPTOGAMS_ARMV4_THUMB_FLAG = -Wa,--noexecstack
+   endif
+   SRCS += aes_armv4.S sha1_armv4.S sha256_armv4.S sha512_armv4.S
+ endif
+@@ -1583,6 +1583,9 @@ NOSTD_CXXFLAGS=$(filter-out -stdlib=%,$(
+ 
+ # Cryptogams ARM asm implementation. AES needs -mthumb for Clang
+ aes_armv4.o : aes_armv4.S
++	echo CPPFLAGS=$(CPPFLAGS)
++	echo NOSTD_CXXFLAGS=$(NOSTD_CXXFLAGS)
++	echo CRYPTOGAMS_ARMV4_THUMB_FLAG=$(CRYPTOGAMS_ARMV4_THUMB_FLAG)
+ 	$(CXX) $(strip $(CPPFLAGS) $(NOSTD_CXXFLAGS) $(CRYPTOGAMS_ARMV4_THUMB_FLAG) -c) $<
+ 
+ # SSSE3 or NEON available