diff --git a/v2_install/compile_image.sh b/v2_install/compile_image.sh
index c17cd25..35168a0 100755
--- a/v2_install/compile_image.sh
+++ b/v2_install/compile_image.sh
@@ -3,28 +3,40 @@
 UA_STRING="Mozilla/5.0 (Macintosh; Intel Mac OS X 12_4) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.4 Safari/605.1.15"
 DL_URL=$(wget --header="Accept: text/html" --user-agent="$UA_STRING" -qO- https://support.wyze.com/hc/en-us/articles/360024852172-Release-Notes-Firmware | grep -Eo "(http|https)://[a-zA-Z0-9./?=_-]*" | grep /v2/ |   sort -t . -k2r,5 | grep demo | head -1)
 
-echo "create work directory"
+echo "checking for tools"
+command -v wget >/dev/null 2>&1 || { echo >&2 "wget is not installed.  Aborting."; exit 1; }
+command -v mkimage >/dev/null 2>&1 || { echo >&2 "mkimage is not installed.  Aborting."; exit 1; }
+command -v unzip >/dev/null 2>&1 || { echo >&2 "unzip is not installed.  Aborting."; exit 1; }
+
+echo "create temporary work directory"
 mkdir v2_ro
 
-echo "download latest firmware"
-wget $DL_URL -P ./v2_ro/
+echo "check for local zip"
+if [ -f demo_4.9.8.1002.zip ]; then
+	echo "local archive found"
+	mv demo_4.9.8.1002.zip ./v2_ro/
+else
+	echo "local archive not found"
+	echo "downloading latest firmware"
+	wget $DL_URL -P ./v2_ro/
+fi
 
-echo "extracting firmware to workdir"
+echo "extracting firmware to temporary work directory"
 unzip v2_ro/demo_4.9.8.1002.zip -d ./v2_ro/
 
-echo "create firmware dir"
-mkdir v2_ro/tmp_dir
+echo "create firmware directory"
+mkdir v2_ro/fw_dir
 
-echo "unpack stock firmware"
-./fw_tool.sh unpack v2_ro/demo_4.9.8.1002.bin v2_ro/tmp_dir
+echo "unpack stock firmware image"
+./fw_tool.sh unpack v2_ro/demo_4.9.8.1002.bin v2_ro/fw_dir
 
-echo "replace kernel"
-cp v2_kernel.bin v2_ro/tmp_dir/kernel.bin
+echo "replace factory kernel"
+cp v2_kernel.bin v2_ro/fw_dir/kernel.bin
 
-echo "pack firmware with new kernel"
-./fw_tool.sh pack v2_ro/tmp_dir/ demo.bin
+echo "pack firmware image with new kernel"
+./fw_tool.sh pack v2_ro/fw_dir/ demo.bin
 
-echo "md5sum is:  " `md5sum demo.bin`
+echo "remove temporary work directory"
 rm -rf v2_ro
 
 echo "demo.bin ready.  Please copy demo.bin to your memory card"