From 749f22c72ba5ed14b75d609f084ca656a6bc44f7 Mon Sep 17 00:00:00 2001
From: Michel Roegl-Brunner <michel.roegl-brunner@htl-braunau.at>
Date: Fri, 16 May 2025 10:55:18 +0200
Subject: [PATCH] Enhance config_file function to improve MAC address
 validation by allowing unset variable expansion

---
 misc/build.func | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/misc/build.func b/misc/build.func
index 2e99761..8bc9bb2 100644
--- a/misc/build.func
+++ b/misc/build.func
@@ -1186,7 +1186,7 @@ config_file() {
     fi
   fi
 
-  if [[ -n "${MAC}" ]]; then
+  if [[ -n "${MAC-}" ]]; then
     if [[ "$MAC" =~ ^([A-Fa-f0-9]{2}:){5}[A-Fa-f0-9]{2}$ ]]; then
       echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
       MAC=",hwaddr=$MAC"