Please clarify BBB boot option


From Yocto project link:

It has the following:

The Beaglebone Black has eMMC, while the White does not. Pressing the USER/BOOT button when powering on will temporarily change the boot order. But for the sake of simplicity, these instructions assume you have erased the eMMC on the Black, so its boot behavior matches that of the White and boots off of SD card. To do this, issue the following commands from the u-boot prompt:

# mmc dev 1
# mmc erase 0 512

To further tailor these instructions for your board, please refer to the documentation at and

  1. I don’t find any description about “Pressing the USER/BOOT button”. What is the detail information after pressing the USER/BOOT button?

  2. The above # lines are an alternative to the “Pressing the USER/BOOT button”?

  3. I don’t find the documentation with the link: . Can you point me to the documentation address?


What is the problem? This is a (hardware) button on your BBB which needs to be pressed on power-up in order to boot from eMMC - that’s all.

And there is a document that describes the hardware on the board and there is a section on that button in it. Sorry no audio book available.