On my hardware, esptool reports
MAC: 7c:df:a1:02:6c:b8
after this change, the USB descriptor says SerialNumber: 7CDFA1026CB8
and microcontroller.cpu.id has
>>> "".join("%02x" % byte for byte in microcontroller.cpu.uid)
'c7fd1a20c68b'
Note that the nibble-swapping between USB and cpu.uid is typical.
For instance, an stm32 board has USB SerialNumber
24002500F005D42445632302 but hex-converted microcontroller.cpu.id
420052000f504d4254363220.
