Can't flash firmware

I have a Pixhawk 3 Pro running ArduCopter. I want to flash PX4 on it but I keep getting the following error:

Image size of 1727681 is too large for board flash size 1032192
Upgrade cancelled

Here’s the screenshot:

Can someone please help?

I don’t have a 3 but from you screen shot it looks like you are trying to load the version for the 4.
I’m thinkin you should ues px4_fmu-v3_default.px4

No, that’s the correct version of firmware for this board. See:

I am getting the same error. How to resolve? Thanks.