just double checking:
the file is named PX570PRO.CAP
the usb device is formated fat32
the file is in the root directory
you have the usb drive plugged into the bottom left usb port
your using bios version 2802 downloaded from:
https://www.asus.com/us/Motherboards/PRIME-X570-PRO/HelpDesk_BIOS/
make sure all other hard drives, cd-rom drives, and etc are all disconnected.
if all of the above is true, and it still will not flash you likely have a dead chip. You could pull it off, but odds are your friend would not be able to flash it either. There are several providers out their that will send you a new one with the correct bios already flashed. Looks like a doable solder job.
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a 2 minute search turned up this:
Find many great new & used options and get the best deals for BIOS CHIP - ASUS PRIME X570-P / X570-PRO / ROG STRIX X570-F / X570-I GAMING at the best online prices at eBay! Free shipping for many products!
www.ebay.com
likely, if you put more time in it you could find a better solution. Perhaps your friend.
good luck.