From cc221330ba1dbac71d2214dbcdb3699d74b02e83 Mon Sep 17 00:00:00 2001
From: Ryan Gregg <github@ryangregg.com>
Date: Sun, 19 Jul 2026 10:17:08 -0700
Subject: [PATCH] Fix nRF52 builds: guard SerialEthernetInterface with
 ETHERNET_ENABLED

SerialEthernetInterface.cpp is compiled for every nRF52 target because
PlatformIO builds all .cpp files under src/. It includes
SerialEthernetInterface.h, which unconditionally pulls in
<RAK13800_W5100S.h> -- a library only present in the RAK4631 Ethernet
env's lib_deps. As a result any other nRF52 board (e.g. Heltec T114)
fails to build with 'RAK13800_W5100S.h: No such file or directory'.

Wrap the contents of both files in '#ifdef ETHERNET_ENABLED' so they
compile to empty translation units on non-Ethernet builds. RAK4631
Ethernet envs define ETHERNET_ENABLED and are unaffected.

Fixes #2985
---
 src/helpers/nrf52/SerialEthernetInterface.cpp | 4 ++++
 src/helpers/nrf52/SerialEthernetInterface.h   | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/helpers/nrf52/SerialEthernetInterface.cpp b/src/helpers/nrf52/SerialEthernetInterface.cpp
index 70891023..36a998a4 100644
--- a/src/helpers/nrf52/SerialEthernetInterface.cpp
+++ b/src/helpers/nrf52/SerialEthernetInterface.cpp
@@ -1,3 +1,5 @@
+#ifdef ETHERNET_ENABLED
+
 #include "SerialEthernetInterface.h"
 #include "EthernetMac.h"
 #include <SPI.h>
@@ -262,3 +264,5 @@ bool SerialEthernetInterface::isConnected() const {
 void SerialEthernetInterface::loop() {
   Ethernet.maintain();
 }
+
+#endif // ETHERNET_ENABLED
diff --git a/src/helpers/nrf52/SerialEthernetInterface.h b/src/helpers/nrf52/SerialEthernetInterface.h
index 95ce8a52..b8b4e94b 100644
--- a/src/helpers/nrf52/SerialEthernetInterface.h
+++ b/src/helpers/nrf52/SerialEthernetInterface.h
@@ -1,5 +1,7 @@
 #pragma once
 
+#ifdef ETHERNET_ENABLED
+
 #include "helpers/BaseSerialInterface.h"
 #include <SPI.h>
 #include <RAK13800_W5100S.h>
@@ -76,3 +78,5 @@ class SerialEthernetInterface : public BaseSerialInterface {
   #define ETHERNET_DEBUG_PRINTLN(...) {}
   #define ETHERNET_DEBUG_PRINT_IP(...) {}
 #endif
+
+#endif // ETHERNET_ENABLED