The iMX are capable of muxing almost all their BGA pads for the functions available, so USB pads or UARTs can be in surprising places. One must examine the device tree blobs which define what appears where. They’re probably stored in their own partition somewhere.
Took me forever to find the correct UART (1 of 4!) for the board I was playing with (
https://www.axiom-partners.com/ilx702d)