diff --git a/build.sh b/build.sh
index 47fec4a3..79690b54 100755
--- a/build.sh
+++ b/build.sh
@@ -47,8 +47,8 @@ build_firmware() {
   # e.g: RAK_4631_Repeater-v1.0.0-SHA
   FIRMWARE_FILENAME="$1-${FIRMWARE_VERSION_STRING}"
 
-  # export build flags for pio so we can inject firmware version info
-  export PLATFORMIO_BUILD_FLAGS="-DFIRMWARE_BUILD_DATE='\"${FIRMWARE_BUILD_DATE}\"' -DFIRMWARE_VERSION='\"${FIRMWARE_VERSION_STRING}\"'"
+  # add firmware version info to end of existing platformio build flags in environment vars
+  export PLATFORMIO_BUILD_FLAGS="${PLATFORMIO_BUILD_FLAGS} -DFIRMWARE_BUILD_DATE='\"${FIRMWARE_BUILD_DATE}\"' -DFIRMWARE_VERSION='\"${FIRMWARE_VERSION_STRING}\"'"
 
   # build firmware target
   pio run -e $1
@@ -143,8 +143,11 @@ mkdir -p out
 
 # handle script args
 if [[ $1 == "build-firmware" ]]; then
-  if [ "$2" ]; then
-    build_firmware $2
+  TARGETS=${@:2}
+  if [ "$TARGETS" ]; then
+    for env in $TARGETS; do
+      build_firmware $env
+    done
   else
     echo "usage: $0 build-firmware <target>"
     exit 1