and fixed a UART noise bug

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) {}
 

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

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();