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
USB 2.0 / 3.0 interface
micro-5pin data cable