Patched with shorter boot timeout to be more useful as a rubber duckie.
Those instructions are for macOS.
Download ArduinoISP project from https://code.google.com/archive/p/mega-isp/downloads and apply this patch:
diff --git a/ArduinoISP.pde b/ArduinoISP.pde
index 899a4cc..b1f411f 100644
--- a/ArduinoISP.pde
+++ b/ArduinoISP.pde
@@ -99,7 +99,7 @@ void heartbeat() {
if (hbval < 32) hbdelta = -hbdelta;
hbval += hbdelta;
analogWrite(LED_HB, hbval);
- delay(40);
+ delay(20);
}
otherwise avrdude will report either of those messages and programming will fail
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_cmd(): programmer is out of sync
Connect Arduino UNO and upload this sketch.
With Leostick wired as shown in the official tutorial, quit Arduino IDE and reset Arduino with the onboard switch.
Detect what port Arduino is connected on with ls /dev/cu.usbmodem* (eg /dev/cu.usbmodem371).
$HEX_FILE is file to built bootloader, such as Caterina-LeoStick.hex.
Flash Leostick bootloader with this command:
avrdude -cavrisp -b19200 -v -patmega32u4
-P $PORT\
-e \
-Ulock:w:0x3F:m \
-Uefuse:w:0xcb:m \
-Uhfuse:w:0xd8:m \
-Ulfuse:w:0xff:m \
-Uflash:w:$HEX_FILE:i \
-Ulock:w:0x2F:m