From 9e2d49e225aa1dd0d8c53ee29a18576e2c28c6d8 Mon Sep 17 00:00:00 2001
From: Firmware Batman <firmware@comma.ai>
Date: Sat, 29 Jul 2017 19:50:35 -0700
Subject: [PATCH] and fixed a UART noise bug

---
 board/bootstub.c    | 1 -
 board/main.c        | 8 ++++++--
 board/spi_flasher.h | 3 ---
 3 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/board/bootstub.c b/board/bootstub.c
index 16bc992e4..e53a6d2fe 100644
--- a/board/bootstub.c
+++ b/board/bootstub.c
@@ -23,7 +23,6 @@
 #include "drivers/usb.h"
 //#include "drivers/uart.h"
 
-void uart_init(USART_TypeDef *u, int baud) {}
 int puts(const char *a) { return 0; }
 void puth(unsigned int i) {}
 
diff --git a/board/main.c b/board/main.c
index f4333d48f..52b58ff22 100644
--- a/board/main.c
+++ b/board/main.c
@@ -431,8 +431,12 @@ int main() {
   puts(is_entering_bootmode ? "  ESP wants bootmode\n" : "  no bootmode\n");
   gpio_init();
 
-  // enable main uart
-  uart_init(USART2, 115200);
+  // enable main uart if it's connected
+  if (has_external_debug_serial) {
+    // WEIRDNESS: without this gate around the UART, it would "crash", but only if the ESP is enabled
+    // assuming it's because the lines were left floating and spurious noise was on them
+    uart_init(USART2, 115200);
+  }
 
 #ifdef PANDA
   // enable ESP uart
diff --git a/board/spi_flasher.h b/board/spi_flasher.h
index 4159c48c5..894dd20be 100644
--- a/board/spi_flasher.h
+++ b/board/spi_flasher.h
@@ -140,9 +140,6 @@ void soft_flasher_start() {
   set_gpio_alternate(GPIOA, 12, GPIO_AF10_OTG_FS);
   GPIOA->OSPEEDR = GPIO_OSPEEDER_OSPEEDR11 | GPIO_OSPEEDER_OSPEEDR12;
 
-  // enable main uart
-  uart_init(USART2, 115200);
-
   // flasher
   spi_init();