同じ場所にあったoptiboot使ったらちゃんと動いたけどどうよ?
Current flash contents:
0123456789ABCDEFGHIJKLMNOPQRSTUVW
Type 128 characters to store in flash:
000000000011111111112222222222333333333344444444445555555555
66666666667777777777888888888899999999990000000
All chars received
Erasing buffer
Writing to temporary flash buffer
Writing buffer to flash
Write done, thank you!
Now you can reset or power cycle board and check for new contents!