APM 2.5.2 firmware verification error

I have this old but in perfect condition APM 2.5.2 which i was trying to update to latest supported firmware but I keep getting verification error message despite the fact that it looks as though fw seems to be uploading ok.

Any thoughts?

Used to get this type of error, and other verification errors on APM.
Turned out to be combinations of not real good USB cables, slow PC, and not running the latest Mission Planner.

The other thought is the versions compatible with the APM
I know copter is maxed out at 3.2.1 for the APM.
Not sure about plane.
Mission Planner is supposed to see the board attached and load the appropriate firmware, but I see copter 3.4.4 is on the screen.
Not sure about plane and what versions will fir on the APM but I know it is getting close to EOL.
Might be worth checking there.

Thank you.
My PC is way stronger than needed
I have tried many different USB cables - all are good quality and works great with other Flight controllers so it looks like a specific flight controller issue, and as you can see i am running latest MP.

There is defiantly something wrong with this APM board. it works, all parameters are there, i can set it up, and i will try to fly it, but what’s bothering me is why i get this error, if it means there is a chance it will fail during flight, and… if i can somehow refresh eeprom/firmware maybe using arduino IDE to upload firmware and not only via MP.

Can you please direct me how to download arduplane from GITHUB, compile it and upload it?