Beagle board MMC boot myths?

Booting a Beagle board from an MMC/SD should be easier than what people tell you

Beagle boardAt the time of this writing, most documentation that you can find on the web about the Beagle board will tell you that you need to take special preparation steps if you wish to boot your board on an MMC/SD card:

  • The card requires a special geometry: 255 heads and 63 sectors per track
  • The first partition on the card, with a FAT type, must be marked as bootable
  • The X-loader (MLO file), must be copied to the first sectors of the first partition. As a consequence, you should copy this file first.

As my colleague Florent Peyraud and TI engineers started to suspect, all this is not always required. I’ve just made tests with my Rev C2 Beagle board:

  • I took a brand new MMC/SD card. fdisk showed that it had 57 heads and 56 sectors per track.
  • I created the partitions again, and didn’t flag the first one as bootable.
  • After formatting the first partition in FAT32 format, I first copied the u-boot.bin and uImage files, and then the MLO one.

After all this, I had no problem booting my Beagle board on the MMC/SD card. At least with my Rev C2 board, what TI engineers expected was true: the board romcode understood the FAT format, and therefore just needed a file with the MLO name, whatever its physical location on the card.

Does anyone know whether the requirements used to be true with earlier Beagle board romcode releases, or in special cases?

Author: Michael Opdenacker

Michael Opdenacker is the founder of Bootlin, and was its CEO until 2021. He is best known for all the free embedded Linux and kernel training materials that he created together with Thomas Petazzoni. He is always looking for ways to increase performance, reduce size and boot time, and to maximize Linux' world domination. More details...

8 thoughts on “Beagle board MMC boot myths?”

  1. In my experience begin able to boot from MMC depends on the MMC card you have.
    When using the default setup some cards work and some others simply don’t. At least it is clearly not as simple as “it’s a myth” :p

  2. Forwarding a message from TI people…

    They checked with the ROM code people. According to them, it can work with any geometry in most cases. However, there can be very special cases in which it won’t work. There are also errata on this topic.

  3. Deleted a comment by mistake…

    I no longer see the first comment that was posted on this article. I must have deleted it by mistake. If you posted it, don’t hesitate to write it again.

    My apologies!

  4. Same experience here, I incidentally just formatted it with fdisk and it just worked. For the records: I used a standard sandisk 4GB card.

  5. I have a brand new rev.c3 beagle board and i am not able to boot the board. u-boot is not working and i followed all the steps mentioned in the beagle board and e Linux websites to trouble shoot. i am not getting anything on the hyper terminal. i don’t know where the problem lies.

    please can any one helps me in this issue?

  6. Is this myth related with filesystem?
    Is the sequence of file copy required only in case of FAT 32 filesystem ?

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