Missing File While Trying to Load Firmware in APM 2.8 using APM Planner V2.0.20

I’ve been trying to load the Arducopter quad firmware into my APM 2.8. I tried using Mission Planner on an old XP machine with no luck as M.P. requires a .NET Framework package that is no longer available. So this morning I tried installing APM Planner v2.0.20 on my Windwos 10 desktop. I was able to successfully connect to my APM, but when I disconnected and tried to load the firmware the follwing error message was displayed:

Any ideas on where I can obtain this file or suggestions on what to do?

Get a F405 based or if your budget allows H7 based, board they are significantly better than APM2.8 and supported by modern Ardupilot. You will save yourself a lot of time and hair pulling.

Thank you for your reply. Since my original post (and subsequent posts), I was able to find a version of M.P. where I was able to load the firmware into my APM and another separate version that allowed me to calibrate the acceleromter. I was even able to connect to my aircraft wirelessly on my Windows 10 desktop via the telemetry modems. But I was unablle to perform the compass calibration.

I even bought a Pixhawk 2.4.8 (Chinese clone), but was unable to just connect it to either my desktop nor my Windows 11 laptop - got an unrecognized USB device warning from the O/S. I ended up returning it to the seller.

Another problem was not being able to connect my telemetry modem on my Windows 11 laptop to any version of Mission Planner.

I have to say that the quality of Mission Planner has diminished since the last couple of years that I last used it until my Tarot Ironman crashed. I suspect that this is due to the fact that the Ardupilot Group is not a for profit software company and so there is no incentive to developing robust regression test suites, nor following other generally accepted software development practices.

I get that the APM F.C. is obsolete (it was when I got into this hobby years ago), but as long as these devices are still being sold, there is an expectation on the part of the customer that there is a stable version of supporting software. Maybe you guys no longer want to support M.P. for APM or Pixhawk 2.4.x but at least you could point to a stable legacy version that one could use with some degree of confidence that it will work.

As a customer, I would be willing to pay for M.P. if there was a S/W company that woulld support it. But from what I’ve seen that option doesn’t exist. And I have little confidence that even if I took your advice that I won’t have additional headaches, given that I can’t even get my telemetry moden to un on a Windows 11 laptop using the latest version of M.P.

I have seen on YouTube, guys who have successfully done campass calibations with APM 2.8 as recently as a year ago, so I know that it is possible to do so. I have ordered another APM with a matching GPS/compass module and jumper - when it arrives I will load the foirmware, calibrate the accelerometer and attempt the compass calibration using the included external GPS/compass - if successful, I will install it on my aircraft; if not, then I will abandon the project.