diff --git a/script/bootstrap.bash b/script/bootstrap.bash
index e8c827a..af4644d 100755
--- a/script/bootstrap.bash
+++ b/script/bootstrap.bash
@@ -124,7 +124,7 @@ IMAGE_NAME=$(basename "${IMAGE_URL}" .zip)
 IMAGE_FILE="$IMAGE_NAME".img
 [ -f "$TOOLS_HOME"/images/"$IMAGE_FILE" ] || {
     # unit MB
-    EXPAND_SIZE=4096
+    EXPAND_SIZE=6144
 
     [ -d "$TOOLS_HOME"/images ] || mkdir -p "$TOOLS_HOME"/images
 
diff --git a/script/otbr-setup.bash b/script/otbr-setup.bash
index 9696caa..820f554 100644
--- a/script/otbr-setup.bash
+++ b/script/otbr-setup.bash
@@ -210,7 +210,11 @@ if [ "${REFERENCE_PLATFORM?}" = "ncs" ]; then
     echo 'exit 0' >>/etc/rc.local
 
     # update testharness-discovery script to fix autodiscovery issue
-    sed -i 's/OpenThread_BR/OTNCS_BR/g' /usr/sbin/testharness-discovery
+    if [ "$REFERENCE_RELEASE_TYPE" = "1.2" ]; then
+        sed -i 's/OpenThread_BR/OTNCS_BR/g' /usr/sbin/testharness-discovery
+    else
+        sed -i 's/OpenThread_BR/OTNCS13_BR/g' /usr/sbin/testharness-discovery
+    fi
 
 elif [ "${REFERENCE_PLATFORM?}" = "efr32mg12" ]; then
     # update testharness-discovery script to fix autodiscovery issue