diff --git a/build-tools/build-docker-images/build-stx-images.sh b/build-tools/build-docker-images/build-stx-images.sh
index 085c5d77..345b040b 100755
--- a/build-tools/build-docker-images/build-stx-images.sh
+++ b/build-tools/build-docker-images/build-stx-images.sh
@@ -185,7 +185,7 @@ function build_image_loci {
 
     docker build ${WORKDIR}/loci --no-cache \
         "${BUILD_ARGS[@]}" \
-        --tag ${build_image_name}  2>&1 | tee ${WORKDIR}/docker-${LABEL}.log
+        --tag ${build_image_name}  2>&1 | tee ${WORKDIR}/docker-${LABEL}-${OS}-${OPENSTACK_RELEASE}.log
     if [ ${PIPESTATUS[0]} -ne 0 ]; then
         echo "Failed to build ${LABEL}... Aborting"
         RESULTS_FAILED+=(${LABEL})
@@ -297,7 +297,7 @@ function build_image_docker {
 
     docker build ${docker_src} --no-cache \
         --build-arg "BASE=${BASE}" \
-        --tag ${build_image_name} 2>&1 | tee ${WORKDIR}/docker-${LABEL}.log
+        --tag ${build_image_name} 2>&1 | tee ${WORKDIR}/docker-${LABEL}-${OS}-${OPENSTACK_RELEASE}.log
     if [ ${PIPESTATUS[0]} -ne 0 ]; then
         echo "Failed to build ${LABEL}... Aborting"
         RESULTS_FAILED+=(${LABEL})
diff --git a/build-tools/build-wheels/build-base-wheels.sh b/build-tools/build-wheels/build-base-wheels.sh
index ad3bb9ad..f97dc993 100755
--- a/build-tools/build-wheels/build-base-wheels.sh
+++ b/build-tools/build-wheels/build-base-wheels.sh
@@ -100,6 +100,11 @@ if [ ! -f ${DOCKER_FILE} ]; then
     exit 1
 fi
 
+if [ ! -f ${WHEELS_CFG} ]; then
+    echo "Required file does not exist: ${WHEELS_CFG}" >&2
+    exit 1
+fi
+
 #
 # Check build output directory for unexpected files,
 # ie. wheels from old builds that are no longer in wheels.cfg
@@ -130,6 +135,45 @@ for wheel in $(cat ${WHEELS_CFG} | sed 's/#.*//' | awk -F '|' '{print $1}'); do
     fi
 done
 
+if [ "${OPENSTACK_RELEASE}" = "master" ]; then
+    # Download the master wheel from loci, so we're only building pieces not covered by it
+    MASTER_WHEELS_IMAGE="loci/requirements:master-${OS}"
+
+    # Check to see if the wheels are already present.
+    # If so, we'll still pull to ensure the image is updated,
+    # but we won't delete it after
+    docker images --format '{{.Repository}}:{{.Tag}}' ${MASTER_WHEELS_IMAGE} | grep -q "^${MASTER_WHEELS_IMAGE}$"
+    MASTER_WHEELS_PRESENT=$?
+
+    docker pull ${MASTER_WHEELS_IMAGE}
+    if [ $? -ne 0 ]; then
+        echo "Failed to pull ${MASTER_WHEELS_IMAGE}" >&2
+        exit 1
+    fi
+
+    # Export the image to a tarball.
+    # The "docker run" will always fail, due to the construct of the wheels image,
+    # so just ignore it
+    docker run --name ${USER}_inspect_wheels ${MASTER_WHEELS_IMAGE} noop 2>/dev/null
+
+    echo "Extracting wheels from ${MASTER_WHEELS_IMAGE}"
+    docker export ${USER}_inspect_wheels | tar x -C ${BUILD_OUTPUT_PATH} '*.whl'
+    if [ ${PIPESTATUS[0]} -ne 0 -o ${PIPESTATUS[1]} -ne 0 ]; then
+        echo "Failed to extract wheels from ${MASTER_WHEELS_IMAGE}" >&2
+        docker rm ${USER}_inspect_wheels
+        if [ ${MASTER_WHEELS_PRESENT} -ne 0 ]; then
+            docker image rm ${MASTER_WHEELS_IMAGE}
+        fi
+        exit 1
+    fi
+
+    docker rm ${USER}_inspect_wheels
+
+    if [ ${MASTER_WHEELS_PRESENT} -ne 0 ]; then
+        docker image rm ${MASTER_WHEELS_IMAGE}
+    fi
+fi
+
 if [ "${BUILD_NEEDED}" = "no" ]; then
     echo "All base wheels are already present. Skipping build."
     exit 0
diff --git a/build-tools/build-wheels/build-wheel-tarball.sh b/build-tools/build-wheels/build-wheel-tarball.sh
index a134e31f..4fa8b7ea 100755
--- a/build-tools/build-wheels/build-wheel-tarball.sh
+++ b/build-tools/build-wheels/build-wheel-tarball.sh
@@ -147,18 +147,33 @@ if [ -f ${TARBALL_FNAME} ]; then
 fi
 
 # Download the global-requirements.txt and upper-constraints.txt files
-wget https://raw.githubusercontent.com/openstack/requirements/stable/${OPENSTACK_RELEASE}/global-requirements.txt
+if [ "${OPENSTACK_RELEASE}" = "master" ]; then
+    OPENSTACK_BRANCH=${OPENSTACK_RELEASE}
+else
+    OPENSTACK_BRANCH=stable/${OPENSTACK_RELEASE}
+fi
+
+wget https://raw.githubusercontent.com/openstack/requirements/${OPENSTACK_BRANCH}/global-requirements.txt
 if [ $? -ne 0 ]; then
     echo "Failed to download global-requirements.txt" >&2
     exit 1
 fi
 
-wget https://raw.githubusercontent.com/openstack/requirements/stable/${OPENSTACK_RELEASE}/upper-constraints.txt
+wget https://raw.githubusercontent.com/openstack/requirements/${OPENSTACK_BRANCH}/upper-constraints.txt
 if [ $? -ne 0 ]; then
     echo "Failed to download upper-constraints.txt" >&2
     exit 1
 fi
 
+# Delete $SKIP_CONSTRAINTS from upper-constraints.txt, if any present
+for name in ${SKIP_CONSTRAINTS[@]}; do
+    grep -q "^${name}===" upper-constraints.txt
+    if [ $? -eq 0 ]; then
+        # Delete the module
+        sed -i "/^${name}===/d" upper-constraints.txt
+    fi
+done
+
 # Copy the base and stx wheels, updating upper-constraints.txt as necessary
 for wheel in ../base/*.whl ../stx/wheels/*.whl; do
     # Get the wheel name and version from the METADATA
diff --git a/build-tools/build-wheels/docker/master-wheels.cfg b/build-tools/build-wheels/docker/master-wheels.cfg
new file mode 100644
index 00000000..07fc5463
--- /dev/null
+++ b/build-tools/build-wheels/docker/master-wheels.cfg
@@ -0,0 +1,9 @@
+#
+# git: wheelname|git|git-source|basedir|branch
+# tar: wheelname|tar|wget-source|basedir
+# pypi: wheelname|pypi|wget-source
+# zip: wheelname|zip|wget-source|basedir
+#
+# If fix_setup must be called, add |fix_setup at the end of the line
+#
+lz4-0.9.0-cp27-none-linux_x86_64.whl|git|https://github.com/python-lz4/python-lz4|python-lz4|v0.9.0
diff --git a/build-tools/build-wheels/get-stx-wheels.sh b/build-tools/build-wheels/get-stx-wheels.sh
index f5f553c6..e24528b8 100755
--- a/build-tools/build-wheels/get-stx-wheels.sh
+++ b/build-tools/build-wheels/get-stx-wheels.sh
@@ -84,8 +84,8 @@ function get_wheels_files {
     find ${GIT_LIST} -maxdepth 1 -name "${OS}_${OPENSTACK_RELEASE}_wheels.inc"
 }
 
-WHEELS_FILES=$(get_wheels_files)
-if [ $(echo -n "$WHEELS_FILES" | wc -l) -eq 0 ]; then
+declare -a WHEELS_FILES=($(get_wheels_files))
+if [ ${#WHEELS_FILES[@]} -eq 0 ]; then
     echo "Could not find ${OS} wheels.inc files" >&2
     exit 1
 fi
@@ -100,7 +100,7 @@ cd ${BUILD_OUTPUT_PATH}
 
 # Extract the wheels
 declare -a FAILED
-for wheel in $(sed -e 's/#.*//' ${WHEELS_FILES} | sort -u); do
+for wheel in $(sed -e 's/#.*//' ${WHEELS_FILES[@]} | sort -u); do
     case $OS in
         centos)
             # Bash globbing does not handle [^\-] well,