diff --git a/build-scripts/oe/build.sh b/build-scripts/oe/build.sh
index afe374cb8..d9de83620 100755
--- a/build-scripts/oe/build.sh
+++ b/build-scripts/oe/build.sh
@@ -167,8 +167,22 @@ if [ ! -d openxt ] ; then
     cd openxt
 
     # Fetch the "upstream" layers
-    # Initialise the submodules using .gitmodules
+
     git submodule init
+
+    # Initialise the submodules from the local git mirror by updating .git/config
+    # If there is a copy of the submodule in the local git mirror, use it.
+    for SUBMODULE in $(git config -f .gitmodules --get-regexp path | cut -f2 -d' ')
+    do
+        REPONAME=${SUBMODULE##*/}
+        MIRROR_URL="git://${HOST_IP}/${BUILD_USER}/${REPONAME}"
+        # Detect presence of a mirror repo by using git's ls-remote command:
+        if git ls-remote "${MIRROR_URL}" >/dev/null 2>/dev/null
+        then
+            git config -f .git/config --replace-all submodule."${SUBMODULE}".url "${MIRROR_URL}"
+        fi
+    done
+
     # Clone the submodules, using their saved HEAD
     git submodule update --checkout
     # Update the submodules that follow a branch (update != none)
diff --git a/build-scripts/setup.sh b/build-scripts/setup.sh
index 95cb9f430..e332c6149 100755
--- a/build-scripts/setup.sh
+++ b/build-scripts/setup.sh
@@ -273,7 +273,19 @@ if [ ! -d ${GIT_ROOT_PATH}/${BUILD_USER} ]; then
         git clone --quiet --mirror https://github.com/OpenXT/${repo}.git
     done
     echo "Done"
+    echo "Mirroring the upstream layer repositories..."
+    # Obtain the URLs of the submodule repositories from a temporary clone of openxt.git
+    TMP_CLONE_DIR=$(mktemp -d /tmp/setup-openxt.XXXXX)
+    git clone --depth 1 --quiet file://${GIT_ROOT_PATH}/${BUILD_USER}/openxt.git \
+        "${TMP_CLONE_DIR}/openxt"
+    for repo_url in \
+        $(git config -f "${TMP_CLONE_DIR}/openxt/.gitmodules" --get-regexp url | cut -f2 -d' ')
+    do
+        git clone --quiet --mirror ${repo_url}
+    done
     cd - > /dev/null
+    rm -rf ${TMP_CLONE_DIR}
+    echo "Done"
     chown -R ${BUILD_USER}:${BUILD_USER} ${GIT_ROOT_PATH}/${BUILD_USER}
 fi