iPhone Xr randomly bootloop at random moment

So this kernel panic refers to the inability for some components to receive communication it needs. I2C is an inter-chip communication protocol. In this case it seems as though the CPU cannot receive an interrupt from somewhere it’s expecting to send one. I2C0 (there are a few groups for I2C communications) only runs through a limited number of components. But it runs through the charge port flex cable, the battery connector (and so presumably the battery) and the cable from the top of the display to the logic board (the one for receiver speaker/mic and whatever other display mounted components) as well as a few board components.

I’m not 100% sure what AD5860 is. But it sounds like something involved in this communication net. Do you have issues with audio at all or battery? Since that’s what seems to be involved in this I2C Group. If you’re repair savvy, I might open this device up and do a quick inspection, reseat the cables for the dock, display and battery and see if that makes a difference. I might try replacing the charge port flex in particular. Otherwise this may be a board level issue.

UPDATE: On the chance that others stumble into this question. AD5860 is also known as the Sakonnet chip. It is a part of Taptic Engine functionality, getting data from the magnetic sensors inside of the module itself. This chip is very long and narrow because it is often mounted on the side of the Taptic Engine (like the XR mentioned here), although it is sometimes on the board itself (in the iPhone 12 series).

Panics which mention it are more likely to result from a faulty dock flex. The Dock flex is the conduit for Taptic data between the vibe motor and the log board since there is no direct connection between the two.

This is not always the case. Because i2c data is also received by the Sakonnet chip, issues with other components that are in that same i2c group could also be affected.