May I know is the Eagleye 530s board is able to direct boot into OS when powered through USB or 5V DC port without having to press the S1 switch?
Yes, Find the D401 diode as below picture, remove D401 diode by soldering, short the D401’s two pins by soldering a solder dot.
There are lots of small components around the diode to be removed and my hot air gun will just blow off all of them.
Can I just short the push button?
it is the same, just route the signal to ground. thanks.