fix: detach reboot command to avoid false SSH failures

bin/netupgrade

@@ -201,8 +201,11 @@ runCmd() { # $1=host $2=name $3=cmd
 
 	case ${CMD} in
 		reboot)
-			if ! runSSH "${HOST}" reboot | tee -a "${LOGFILENAME}"; then
+			echo "reboot (detached)" | tee -a "${LOGFILENAME}"
+			if ! runSSH "${HOST}" sh -c 'nohup sh -c "reboot || /sbin/reboot || shutdown -r now" >/dev/null 2>&1 </dev/null &' | tee -a "${LOGFILENAME}"; then
 				ERROR=1
+			else
+				sleep 1
 			fi
 		;;
 		apt)