A faulty power meter, huh? Well, I can't say I'm surprised. Shimano's Dura-Ace R9100-P has been notorious for its finicky calibration process since its release.
First things first, make sure you've followed the manual to the letter. I know, I know, you've already said you did, but let's face it, manuals can be as clear as mud sometimes. Double-check the battery and crankset installation, ensuring they're properly aligned and tightened.
If you've done all that, and it's still not working, I'd wager you've encountered one of the common issues with this model. Sometimes, the power meter's sensors can become misaligned or damaged, causing calibration failure. I'd recommend taking it to a professional mechanic to have it inspected and realigned if necessary.
But, let's be real, Dura-Ace R9100-P is known for its capricious behavior, and sometimes, no matter what you do, it just refuses to play ball. If you've exhausted all other options, it might be time to consider upgrading to a more reliable power meter.
As for hidden settings or secret handshakes, I'm afraid there's no magic bullet here. Calibration failures are usually caused by mechanical issues, and there's no amount of technical jargon that can change that fact. So, buckle up, grab a wrench, and get ready to do some good old-fashioned troubleshooting.