I have the trouble of the USB serial port with Arduboy.
The serial port disappears when the transfer is started.
Please let me know how to recover that.
(1) Turn on Arduboy
(2) Push the reset button of Arduboy
(3) (The serial port can be found at the time)
(4) (Red and orange LED turn on)
(5) Open Arduino IDE and read the sketch “Helloworld”.
(6) Push send button of IDE
(7) (When IDE start transfer, the serial port disappears immediately.)
(8) (After that, the green and yellow LED flash randomly.)
Here is the video:
Before the issue above, I sent the firmware for devkit below  to my Arduboy 1.0 with the batch file  mistakenly. (A)
 Tiny depth - taste of game watch
After that, I also sent another large image. (B)
So I think the cause is either of (A) or (B).
I already tried:
- How to Reset Arduboy if it's Bricked -> serial port disappears again.
- I try to change my USB cable but it goes the same.
- Arduboy: not for devkit
- IDE: Arduino IDE 1.6.9
- OS: Windows 10 Home