diff --git a/Firmware/lcd.cpp b/Firmware/lcd.cpp
index fd3e1328..71948789 100644
--- a/Firmware/lcd.cpp
+++ b/Firmware/lcd.cpp
@@ -189,9 +189,10 @@ static void lcd_begin(uint8_t clear)
 	#endif
 }
 
-static void lcd_putchar(char c, FILE *)
+static int lcd_putchar(char c, FILE *)
 {
 	lcd_write(c);
+	return 0;
 }
 
 void lcd_init(void)