diff --git a/packages/bsp/common/usr/lib/armbian/armbian-firstlogin b/packages/bsp/common/usr/lib/armbian/armbian-firstlogin
index 21d2a45389cf..b9bda297aa2a 100755
--- a/packages/bsp/common/usr/lib/armbian/armbian-firstlogin
+++ b/packages/bsp/common/usr/lib/armbian/armbian-firstlogin
@@ -786,6 +786,14 @@ set_user_icon() {
 
 if [[ -f /root/.not_logged_in_yet ]] && tty -s; then
 
+	# tty1, the serial console and an early ssh login all start the setup at once.
+	# Let the first one own it, or they race each other through the prompts.
+	exec 9> /run/armbian-firstlogin.lock || exit 1
+	if ! flock -n 9; then
+		echo -e "\nFirst login setup is already running in another session.\n"
+		exit 0
+	fi
+
 	. /root/.not_logged_in_yet
 
 	# override configuration from URL
@@ -926,18 +934,6 @@ if [[ -f /root/.not_logged_in_yet ]] && tty -s; then
 			fi
 		fi
 
-		# Get current session identifiers
-		current_tty=$(tty | sed 's:/dev/::')  # e.g., "tty1"
-		current_pid=$$
-
-		# Kill ONLY other active root SHELL sessions (not login processes)
-		ps -u root -o pid,tty,comm |
-		  awk -v me="$current_tty" -v mypid="$current_pid" '
-		    NR>1 && $2 != "?" && $2 != me && $1 != mypid && $3 ~ /sh$/ {
-		      print $1
-		    }' |
-		  xargs --no-run-if-empty kill -9
-
 		# enable motd
 		chmod +x /etc/update-motd.d/*