Cannot upload Firmware on mini APM v3.1(like APM 2.8)

I tried to upload custom firmware based on AC 3.2.1

but, failed it latest day at 26th dec because of verify failed.

today, I tried again, but also failed because communication error - no connection.

Computer’s Device management (devmgmt.msc) configure is no problem. (rate 115200 / data bit 8 / parity none / stop bit 1 / flow control none)

in the Mission Planner.
I select connected port COM14
and rate set 115200

but firmware uploading isn’t work.

in addition to click on APM:Copter V3.5.4 Quad (APM is changing V3.2.1) does not work.

under progress bar’s text is show ‘reading hex’ first, and show message box “Communication Error - No connection” with ‘upload failed’ under progress bar.

data cable is fine.
and mini APM v3.1 chip is fine, too.

I need solution.

develop environment :
Windows 7 ultimate K x64
Mission Planner 1.3.50 (failed upload on latest version 1.3.52)
Arduino Sketch for ArduPilot Mega 1.0.3
Microsoft .Net Framework 4.6.2
Java 7u79
USB 2.0 / 3.0 interface
micro-5pin data cable

Try using QgrounControl to update your FC instead of Mission Planner. If it works you can then go back to MP for configuration/calibration etc.

mini APM v3.1 (or APM 2.8) cannot use QgroundControl.

That can use only pixhwak.

don’t you understand my problem?

You are right, QGC won’t work for APM.

I had fixed this problem.

This problem’s cause is damaged bootloader.

I refered to “mini APM 3.1 unbrick 2560 bootloader fix” this link []

and using Arduino ISP firmware uploaded on Arduino mega2560 board (can use similar board, like uno, nano, etc…)

through AVRDUDESS program. You can get this here.

First, You need mini APM 3.1 board followed “mini APM 3.1 unbrick 2560 bootloader fix”.

Second, download and install AVRDUDESS.

and Next, refer to this picture, and following discussion.

① Select correct programmer that you have module.

  • If you have “AVR ISP” module, select “Atmel AVR ISP” at the dropdown menu and “Arduino” is “Arduino”.
    ② Port Number connected your APM board(e.g. “COM5”)
    ③ Baud rate. When you using “Arduino ISP”, set default “19200”
    ④ Flash bootloader “.hex” file’s address.
  • If you installed “Arduino Sketch IDE”, default directory is “[Arduino install address]\hardware\arduino\avr\bootloaders\stk500v2\stk500boot_v2_mega2560.hex” or download here.
    ⑤ MCU is you board’s main chip. mini APM 3.1(or APM 2.8) board’s chip is “ATmega2560”
    ⑥ Fill “Option - Force” checkbox, If your process is uncompleted.
    ⑦ This setting is optional. “-v” is showing progress detail.

If your all setting is done, now click “Program!”

and your board revive while blink heartbeat led!