Devices without hardware MAC addresses

I vaguely remember a comment on the Stack Exchange network saying that some Android devices have no permanent hardware MAC address added at the factory or later on. The comment mentioned that [U-Boot](https://en.wikipedia.org/wiki/Das_U-Boot) makes a permanent unchangeable hardware address unnecessary. Are there Android devices that ship with no permanent hardware MAC address in EEPROM, flash storage, or elsewhere? Please mind that this question is not about MAC address randomization.