From 217fde56f967842e80da861c4c3088c078b8554f Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <github@kayari.org>
Date: Thu, 15 Feb 2018 23:54:49 +0000
Subject: [PATCH] Check for missing bootloader port

---
 bin/kaleidoscope-builder | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/bin/kaleidoscope-builder b/bin/kaleidoscope-builder
index 61fc7765..a6fedeaf 100755
--- a/bin/kaleidoscope-builder
+++ b/bin/kaleidoscope-builder
@@ -79,6 +79,10 @@ flash () {
 }
 
 flash_over_usb () {
+    if [ -z "${DEVICE_PORT_BOOTLOADER}" ]; then
+        echo 'DEVICE_PORT_BOOTLOADER is empty (did you hold "Prog" to enable bootloader mode?)' >&2
+        return 1
+    fi
     sleep 1s
     ${AVRDUDE} -q -q -C ${AVRDUDE_CONF} -p${MCU} -cavr109 -D -P ${DEVICE_PORT_BOOTLOADER} -b57600 "-Uflash:w:${HEX_FILE_PATH}:i"
 }