Loading Firmware Error

When I try and load arducopter 3-6-RC4 ChibiOS with the latest download of Mission Planner and get the following error

Mission Planner Version build 1.3.6672.30243


I was also trying to load chibios arduplane 3.9.0beta2 on a pixhawk 2.1 running MP build 28543 (current beta build) and also received the same message. I also had to use 2 different laptops and one PC before I could ever get MP to detect the board. All PC were running the same version of MP.

Also seems to be an error trying to upload arudplane 3.8.5 on a pixhawk 2.1 using the same MP version.

thanks for the report, im fixing this now.

Is this fixed, I just tried it again this morning and am getting the same error updated MP to latest beta(35685) build before trying.

I just replied to a duplicate post here with what resolved this for me: Loading Custom Firmware Error