diff --git a/ci/Dockerfile/ubuntu1604 b/ci/Dockerfile/ubuntu1604
index 46f6801..2aaa647 100644
--- a/ci/Dockerfile/ubuntu1604
+++ b/ci/Dockerfile/ubuntu1604
@@ -7,4 +7,4 @@
   build-essential g++ git bison flex unzip \
   cpio vim-common lsb-release \
   libxml-simple-perl libxml-sax-perl libxml2-dev libxml2-utils xsltproc \
-  wget bc libssl-dev
+  wget bc libssl-dev python-matplotlib python-numpy graphviz eatmydata
diff --git a/ci/build-all-defconfigs.sh b/ci/build-all-defconfigs.sh
index 839d30a..0ab53bf 100755
--- a/ci/build-all-defconfigs.sh
+++ b/ci/build-all-defconfigs.sh
@@ -8,18 +8,24 @@
 
 DEFCONFIGS=();
 
-while getopts "o:p:r" opt; do
+SDK_DIR=""
+
+while getopts "o:p:rs:" opt; do
   case $opt in
     o)
       echo "Output directory: $OPTARG"
       OUTDIR="$OPTARG"
       ;;
+    s)
+      echo "SDK is in: $OPTARG"
+      SDK_DIR=$OPTARG
+      ;;
     p)
       echo "Platforms to build: $OPTARG"
       PLATFORM_LIST="$OPTARG"
       ;;
     r)
-      echo "Build legal-info for release"
+      echo "Build legal-info etc for release"
       BUILD_INFO=1
       ;;
     \?)
@@ -61,26 +67,35 @@
 	export BR2_DL_DIR=${DL_DIR}
 fi
 
+if [ -f $(ldconfig -p | grep libeatmydata.so | tr ' ' '\n' | grep /|head -n1) ]; then
+    export LD_PRELOAD=${LD_PRELOAD:+"$LD_PRELOAD "}libeatmydata.so
+fi
+
 for i in ${DEFCONFIGS[@]}; do
-        rm -rf output/*
-        op-build $i
-        echo 'BR2_CCACHE=y' >> output/.config
-        echo "BR2_CCACHE_DIR=\"$CCACHE_DIR\"" >> output/.config
-        echo 'BR2_CCACHE_INITIAL_SETUP=""' >> output/.config
-
-        op-build olddefconfig
-        op-build
+	export O=${OUTDIR}-$i
+	rm -rf $O
+        op-build O=$O $i
+	./buildroot/utils/config --file $O/.config --set-val BR2_CCACHE y
+        ./buildroot/utils/config --file $O/.config --set-str BR2_CCACHE_DIR $CCACHE_DIR
+	if [ -d "$SDK_DIR" ]; then
+	    ./buildroot/utils/config --file $O/.config --set-val BR2_TOOLCHAIN_EXTERNAL y
+	    ./buildroot/utils/config --file $O/.config --set-str BR2_TOOLCHAIN_EXTERNAL_PATH $SDK_DIR
+	    ./buildroot/utils/config --file $O/.config --set-val BR2_TOOLCHAIN_EXTERNAL_CUSTOM_GLIBC y
+	    ./buildroot/utils/config --file $O/.config --set-val BR2_TOOLCHAIN_EXTERNAL_CXX y
+	    # FIXME: How do we work this out programatically?
+	    ./buildroot/utils/config --file $O/.config --set-val BR2_TOOLCHAIN_EXTERNAL_GCC_6 y
+	    ./buildroot/utils/config --file $O/.config --set-val BR2_TOOLCHAIN_EXTERNAL_HEADERS_4_18 y
+	fi
+        op-build O=$O olddefconfig
+        op-build O=$O
         r=$?
-
-        if [ ${BUILD_INFO} = 1 ] && [ $r = 0 ]; then
-                op-build legal-info
-                mv output/legal-info ${OUTDIR}/$i-legal-info
-        fi
-
-        mkdir ${OUTDIR}/$i-images
-        mv output/images/* ${OUTDIR}/$i-images/
-        mv output/.config ${OUTDIR}/$i-images/.config
-        lsb_release -a > ${OUTDIR}/$i-images/lsb_release
+	if [ ${BUILD_INFO} = 1 ] && [ $r = 0 ]; then
+	    op-build O=$O legal-info
+	    op-build O=$O graph-build
+	    op-build O=$O graph-size
+	    op-build O=$O graph-depends
+	fi
+	lsb_release -a > $O/lsb_release
         if [ $r -ne 0 ]; then
         	exit $r
         fi
diff --git a/ci/build-sdk.sh b/ci/build-sdk.sh
new file mode 100755
index 0000000..8267af3
--- /dev/null
+++ b/ci/build-sdk.sh
@@ -0,0 +1,33 @@
+#!/bin/bash
+
+set -ex
+set -eo pipefail
+
+if [ -z "$1" ]; then
+	echo "No build distro specified"
+	exit 1;
+fi
+
+if [ -z "$2" ]; then
+	echo "No defconfig to build SDK from specified"
+	exit 1;
+fi
+
+if [ -z "$CCACHE_DIR" ]; then
+	CCACHE_DIR=`pwd`/.op-build_ccache
+fi
+
+shopt -s expand_aliases
+source op-build-env
+
+if [ -n "$DL_DIR" ]; then
+	unset BR2_DL_DIR
+	export BR2_DL_DIR=${DL_DIR}
+fi
+
+export O=`pwd`/output-$1-$2/
+op-build O=$O $2
+./buildroot/utils/config --file $O/.config --set-val BR2_CCACHE y
+./buildroot/utils/config --file $O/.config --set-str BR2_CCACHE_DIR $CCACHE_DIR
+op-build O=$O olddefconfig
+op-build O=$O sdk
diff --git a/ci/build.sh b/ci/build.sh
index b313291..012aaef 100755
--- a/ci/build.sh
+++ b/ci/build.sh
@@ -2,8 +2,19 @@
 
 CONTAINERS="ubuntu1604 fedora27"
 
-while getopts ":ab:hp:c:r" opt; do
+
+SDK_ONLY=0
+
+while getopts ":ab:hp:c:rs:S" opt; do
   case $opt in
+    s)
+      echo "SDK Cache dir"
+      SDK_CACHE="$OPTARG"
+      ;;
+    S)
+      echo "Build SDK Only"
+      SDK_ONLY=1
+      ;;
     a)
       echo "Build firmware images for all the platforms"
       PLATFORMS=""
@@ -26,6 +37,8 @@
       echo "-a          Build firmware images for all the platform defconfig's."
       echo "-b DIR      Bind DIR to container."
       echo "-p          List of comma separated platform names to build images for particular platforms."
+      echo "-s DIR      SDK cache dir."
+      echo "-S          Build SDK only"
       echo "-c          Container to run in"
       echo "Example:DOCKER_PREFIX=sudo ./ci/build.sh -a"
       echo -e "\tDOCKER_PREFIX=sudo ./ci/build.sh -p firestone"
@@ -62,12 +75,12 @@
          -t $1 $2
 }
 
-env
+function toolchain_hash
+{
+    echo -n 'toolchain-'$((git submodule ; cd openpower/configs/; cat `ls -1 |grep '_defconfig$'|sort`)|sha1sum |sed -e 's/ .*//')
+}
 
-if [ -d output-images ]; then
-	echo 'output-images already exists!';
-	exit 1;
-fi
+env
 
 for distro in $CONTAINERS;
 do
@@ -108,13 +121,26 @@
 ${DL_DIR_ENV}
 ${CCACHE_DIR_ENV}
 EOF
-)
+		  )
 	$DOCKER_PREFIX docker build --network=host -t openpower/op-build-$distro - <<< "${Dockerfile}"
-	mkdir -p output-images/$distro
-	run_docker openpower/op-build-$distro "./ci/build-all-defconfigs.sh -o output-images/$distro -p $PLATFORMS ${release_args}"
-	if [ $? = 0 ]; then
-		mv *-images output-$distro/
+	if [ -d "$SDK_CACHE" ]; then
+	    SDK_DIR=$SDK_CACHE/$(toolchain_hash)-$distro
+	    if [ ! -d "$SDK_DIR" ]; then
+		chmod +x ci/build-sdk.sh
+		run_docker openpower/op-build-$distro "./ci/build-sdk.sh $distro witherspoon_defconfig"
+		mv output-$distro-witherspoon_defconfig $SDK_DIR
+		$SDK_DIR/host/relocate-sdk.sh
+	    fi
+	    sdk_args="-s $SDK_DIR/host"
 	else
+	    sdk_args=""
+	fi
+
+	if [ $SDK_ONLY == 0 ]; then
+	    run_docker openpower/op-build-$distro "./ci/build-all-defconfigs.sh -o `pwd`/output-$distro -p $PLATFORMS ${release_args} ${sdk_args}"
+	fi
+
+	if [ $? != 0 ]; then
 		exit $?;
 	fi
 done;