No etho0 device on BBB

I followed the instructions found at Build U-Boot and Linux Kernel for Beaglebone and Beaglebone Black | Longer Vision Technology
except I used never versions of the kernel 5.10.0

to build u-boot and a linux kernel. After following all the instructions the kernel boots but it doesn’t detect/create a eth0 interface. This probably means it is not loading a driver for the interface. However, This driver should be supported in kernel.

How can I debug this issue?