From 680574dc07e2f734c620d58a323ddbbe038ca856 Mon Sep 17 00:00:00 2001
From: l5y <220195275+l5yth@users.noreply.github.com>
Date: Tue, 2 Jun 2026 11:55:49 +0200
Subject: [PATCH] Fix LinuxHardwareI2C fd lifecycle

---
 cores/portduino/linux/LinuxHardwareI2C.cpp | 4 +++-
 cores/portduino/linux/LinuxHardwareI2C.h   | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/cores/portduino/linux/LinuxHardwareI2C.cpp b/cores/portduino/linux/LinuxHardwareI2C.cpp
index 0857b00..9492347 100644
--- a/cores/portduino/linux/LinuxHardwareI2C.cpp
+++ b/cores/portduino/linux/LinuxHardwareI2C.cpp
@@ -36,12 +36,14 @@ namespace arduino {
     void LinuxHardwareI2C::begin(const char * device) {
         if (!hasBegun) {
             i2c_file = open(device, O_RDWR);
-            hasBegun = true;
+            if (i2c_file >= 0)
+                hasBegun = true;
         }
     }
     void LinuxHardwareI2C::end() {
         if (hasBegun) {
             close(i2c_file);
+            i2c_file = -1;
             hasBegun = false;
         }
     }
diff --git a/cores/portduino/linux/LinuxHardwareI2C.h b/cores/portduino/linux/LinuxHardwareI2C.h
index 738357c..21dca1b 100644
--- a/cores/portduino/linux/LinuxHardwareI2C.h
+++ b/cores/portduino/linux/LinuxHardwareI2C.h
@@ -20,7 +20,7 @@ enum ResultI2c {
 };
 
 class LinuxHardwareI2C : public HardwareI2C {
-  int i2c_file = 0;
+  int i2c_file = -1; // unopened: fail fast instead of operating on stdin/stdout
 
 public:
   void begin(const char* device);