Dead, no power. All voltage rails test good

So looking for a motherboard specialist who can possibly shed some new light/ideas for me. I'm working on this iPhone 6 that is completely dead. Doesn't recognize plugged in or unplugged w/ good known screen and battery/charging port.

Weird thing is I've literally tested just about every voltage rail from vcc_main to pp_cpu and pp_gpu to 3v0_tristar and literally about 15 other main ones. All test short free and correct voltage.

Phone is not liquid damaged.

Any possible guesses or other ideas to try? I've already replaced pmic twice as well for giggles w/ no improvement.

My next step is to look into bl driver as from my experience this can cause goofiness but once again, incoming and outgoing from that bga test perfect.

Thanks.