From ff4b03b8c1cb594f093ed0229404f254c91fe438 Mon Sep 17 00:00:00 2001
From: Kevin Hester <kevinh@geeksville.com>
Date: Sat, 7 Nov 2020 09:15:28 +0800
Subject: [PATCH] Fix #509 was causing failure on non GPS equipped boards

---
 src/gps/GPS.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/gps/GPS.cpp b/src/gps/GPS.cpp
index aca074ccc..314b4c313 100644
--- a/src/gps/GPS.cpp
+++ b/src/gps/GPS.cpp
@@ -25,9 +25,15 @@ uint8_t GPS::i2cAddress = 0;
 
 GPS *gps;
 
+/// Multiple GPS instances might use the same serial port (in sequence), but we can 
+/// only init that port once.
+static bool didSerialInit;
+
 bool GPS::setupGPS()
 {
-    if (_serial_gps) {
+    if (_serial_gps && !didSerialInit) {
+        didSerialInit = true;
+        
 #ifdef GPS_RX_PIN
         _serial_gps->begin(GPS_BAUDRATE, SERIAL_8N1, GPS_RX_PIN, GPS_TX_PIN);
 #else