diff --git a/.cfg/verify_build b/.cfg/verify_build
index 22d4926..7bcd725 100755
--- a/.cfg/verify_build
+++ b/.cfg/verify_build
@@ -38,10 +38,17 @@ verify_binaries() {
 					return 1
 				fi
 
-				if ! upx --best --lzma --quiet "$full_path" 2>&1 | grep -q "AlreadyPackedException"; then
+				# NOTE: Sometimes production binaries are not writable, which is required by UPX
+				chmod +w "$full_path"
+				upx_output=$(upx --best --lzma --quiet "$full_path" 2>&1)
+				upx_exit_code=$?
+				if [ $upx_exit_code -eq 0 ]; then
 					echo "  [OK] Packing with UPX"
+				elif echo "$upx_output" | grep -q "AlreadyPackedException"; then
+					echo "  [WARN] UPX detected, skipping UPX for $item"
 				else
-					echo "  [WARN] Packing detected, skipping UPX for $item"
+					printf "  [FAIL] UPX failed for %s $item:\n\n%s", "$item", "$upx_output"
+					return 1
 				fi
 			fi
 			cp "$full_path" "${BINARIES_DIR}/${binary_name}"
diff --git a/build.sh b/build.sh
index 95a890b..6bc36ea 100755
--- a/build.sh
+++ b/build.sh
@@ -54,24 +54,20 @@ cleanup_docker() {
 	docker image prune -f
 }
 
-if [ -n "$1" ]; then
-	if [ -d "$1" ]; then
-		build_app "$1"
-	else
-		echo "Directory $1 does not exist"
-		exit 1
-	fi
+if [[ $# -eq 0 ]]; then
+	echo "Building all applications..."
+	for dir in */; do
+		build_app "$dir"
+	done
+elif [[ $1 == "--cleanup" ]]; then
+	cleanup_docker
 else
-	if [ "$1" = "--cleanup" ]; then
-		cleanup_docker
-		exit 0
-	else
-		echo "Building all applications..."
-		for dir in */; do
-			if [ -f "${dir}build.sh" ] && [ -f "${dir}Dockerfile" ]; then
-				build_app "$dir"
-			fi
-		done
-	fi
+	for arg in "$@"; do
+		if [[ -d $arg ]]; then
+			build_app "$arg"
+		else
+			echo "Application directory not found: $arg" >&2
+			exit 1
+		fi
+	done
 fi
-rm -Rf "$TMP_LOG_DIR"
diff --git a/toybox/build.sh b/toybox/build.sh
index 172c5e0..2031a68 100755
--- a/toybox/build.sh
+++ b/toybox/build.sh
@@ -11,7 +11,7 @@ TOYBOX_REPO="https://github.com/landley/toybox.git"
 build_toybox() {
 	. fetch_repo $TOYBOX_REPO
 
-	LDFLAGS="--static -s" make defconfig toybox
+	NOSTRIP="y" make LDFLAGS="--static -s" defconfig toybox
 }
 
 log "Building Toybox"