diff --git a/tasks/scripts/gateway-vm.sh b/tasks/scripts/gateway-vm.sh
index 7228d718c..c8bfb58ee 100755
--- a/tasks/scripts/gateway-vm.sh
+++ b/tasks/scripts/gateway-vm.sh
@@ -58,7 +58,9 @@ normalize_arch() {
 }
 
 normalize_bool() {
-  case "${1,,}" in
+  local val
+  val="$(printf '%s' "$1" | tr '[:upper:]' '[:lower:]')"
+  case "${val}" in
     1|true|yes|on) echo "true" ;;
     0|false|no|off) echo "false" ;;
     *)
diff --git a/tasks/scripts/package-snap.sh b/tasks/scripts/package-snap.sh
index 8c299d352..c7f26e0ce 100755
--- a/tasks/scripts/package-snap.sh
+++ b/tasks/scripts/package-snap.sh
@@ -59,7 +59,9 @@ infer_snap_arch() {
 }
 
 normalize_bool() {
-	case "${1,,}" in
+	local val
+	val="$(printf '%s' "$1" | tr '[:upper:]' '[:lower:]')"
+	case "${val}" in
 	1 | true | yes | on) echo "1" ;;
 	0 | false | no | off) echo "0" ;;
 	*)