diff --git a/android/external/Makefile b/android/external/Makefile
index b4691a9..f80bd18 100644
--- a/android/external/Makefile
+++ b/android/external/Makefile
@@ -25,6 +25,9 @@ build: all
 
 all: build-arm build-arm64 build-x86 build-x86_64
 
+build-common: downloads/downloads.stamp
+	$(MAKE) -C common
+
 build-arm: downloads/downloads.stamp
 	$(MAKE) -C armeabi-v7a
 
diff --git a/android/external/Makefile.conf b/android/external/Makefile.conf
index 45aae11..b8656eb 100644
--- a/android/external/Makefile.conf
+++ b/android/external/Makefile.conf
@@ -4,6 +4,8 @@
 NDK_TOOLCHAIN_COMPILER ?= clang
 ANDROID_API ?= 21
 
+### Boost for android conf
+NCPU ?= 1
 ### Select GNU SED on MacOS.
 
 NDK_UNAME := $(shell uname -s | tr '[A-Z]' '[a-z]')
@@ -16,14 +18,17 @@ else
     TOOLCHAIN_ARCH=linux-x86_64
 endif
 
-### Sequoia deps versions
+
+### Deps versions
 OPENSSL_VERSION=1.1.1h
 GMP_VERSION=6.2.1
 NETTLE_VERSION=3.7.3
+BOOST_VERSION=1.74.0
 
 ### Git deps repos
 EXTERNAL_GIT_REPOS += libetpan|https://gitea.pep.foundation/pEp.foundation/libetpan.git?507ab94fc9609432ef2d4c62770139482f1b5084
 EXTERNAL_GIT_REPOS += sequoia|https://gitlab.com/sequoia-pgp/sequoia.git?openpgp/v1.3.1
+EXTERNAL_GIT_REPOS += boost-for-android|https://github.com/moritz-wundke/Boost-for-Android.git?0e12fbd30cb70b668a117c0913a303acfdaae04f
 
 ### Common variables
 #### Source code targets
diff --git a/android/external/common/Makefile b/android/external/common/Makefile
new file mode 100644
index 0000000..ad3637b
--- /dev/null
+++ b/android/external/common/Makefile
@@ -0,0 +1,58 @@
+# Copyright 2022, pEp Foundation
+# This file is part of pEpJNIAdapter for Android  - MultiArch  build
+# This file may be used under the terms of the GNU General Public License version 3
+# see LICENSE.txt
+
+include ../Makefile.conf
+
+all: build
+
+build: showsetup boost-install
+
+#------------------------------------------------------------------------------#
+# Manage paths for PREFIX, DESTDIR, LOCAL and PATH
+
+EXTERNAL_ROOT := $(shell pwd)
+
+# install root for built files
+DESTDIR = $(EXTERNAL_ROOT)/..
+LOCAL := $(DESTDIR)/output
+
+# debugging stuff
+
+showsetup:
+	@echo "ANDROID_NDK: $(ANDROID_NDK)"
+	@echo "PREFIX: $(LOCAL)"
+	@echo "BOOST_VERSION: $(BOOST_VERSION)"
+	@echo "NCPU: $(NCPU)"
+
+#------------------------------------------------------------------------------#
+# boost
+boost.src.stamp:../downloads/boost-for-android.tar.gz
+	mkdir -p boost
+	cd boost && tar xvf ../$<
+	touch $@
+
+
+boost.stamp: boost.src.stamp
+	cd boost; NCPU=$(NCPU) bash ./build-android.sh $(ANDROID_NDK) \
+		--boost=$(BOOST_VERSION) \
+		--layout=system \
+		--with-libraries=regex,iostreams,system \
+		--prefix=$(LOCAL)
+	touch $@
+
+boost-install: boost.stamp
+
+boost-clean:
+	rm -rf boost.stamp
+
+clean-all: clean
+	rm -rf boost*
+	rm -rf *.git
+	rm -rf *.stamp
+#------------------------------------------------------------------------------#
+
+clean: boost-clean
+
+.PHONY = clean clean-all boost-clean boost-install showsetup
diff --git a/android/external/downloads/Makefile b/android/external/downloads/Makefile
index bc8bdd1..d15cbab 100644
--- a/android/external/downloads/Makefile
+++ b/android/external/downloads/Makefile
@@ -13,10 +13,7 @@ include ../Makefile.conf
 #------------------------------------------------------------------------------#
 # Build parameters
 
-all: downloads.stamp
-
-downloads.stamp: download-iconv download-uuid download-sequoia-deps download-etpan download-sequoia
-	touch $@
+all: download-iconv download-uuid download-sequoia-deps download-etpan download-sequoia download-boost
 
 download-iconv: libiconv-1.15.tar.gz
 
@@ -25,9 +22,11 @@ download-uuid: ossp-uuid_1.6.2.orig.tar.gz
 download-sequoia-deps: openssl-$(OPENSSL_VERSION).tar.gz gmp-$(GMP_VERSION).tar.bz2 \
 						nettle-$(NETTLE_VERSION).tar.gz
 
-download-etpan: libetpan.git.stamp
+download-etpan: libetpan.tar.gz
+
+download-sequoia: sequoia.tar.gz
 
-download-sequoia: sequoia.git.stamp
+download-boost: boost-for-android.tar.gz
 
 # Download source and patch it
 libiconv-1.15.tar.gz:
@@ -56,22 +55,20 @@ nettle-$(NETTLE_VERSION).tar.gz:
 # selected commit is archived in external/$project
 
 define per_repo_targets
-$(1).git.stamp:
+$(1).tar.gz:
 	git clone $(2) $(1).git
 	(cd $(1).git; git archive --format=tar $(3)) > $(1).tar.gz
-	touch $(1).git.stamp
 
-$(1).git_update: $(1).git.stamp
+$(1).git_update: $(1).tar.gz
 	cd $(1).git; git pull
 	rm -rf $(1).tar.gz
 	(cd $(1).git; git archive --format=tar $(3)) > $(1).tar.gz
-	touch $(1).git.stamp
 
 $(1)-clean:
 	rm -rf $(1)
 	rm -f $(1).src.stamp
 
-EXTERNAL_LOCAL_GITS += $(1).git.stamp
+EXTERNAL_LOCAL_GITS += $(1).tar.gz
 EXTERNAL_LOCAL_GITS_UPDATE += $(1).git_update
 EXTERNAL_SRCS += $(1)-src
 EXTERNAL_SRCS_CLEAN += $(1)-clean