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Linux/DRA72: eMMC boot

Fredy Zhang
Expert 5010 points
Part Number: DRA72


Tool/software: Linux

Customer wants to use boot from eMMC. Our Userguide has two partitions in the UDA, the FAT32 and the Linux partition, which are the boot partition and the rootfs partition respectively.

  1. The eMMC mode of  Only UDA(FAT/linux ), whether it can be used as a mass production method? If the eMMC has bad blocks, what effect does it have on the system?
  2. The eMMC mode of  Boot + UDA, Whether it can be used as a mass production method, can you provide more details?
  3. The above two methods, what are our considerations, which method do we recommend to our customers?

Looking forward to your guidance.

Appreciate and thanks.

Best Regards

Fredy

  • 0
    TI__Genius 10180 points

    Fredy,

    There are three ways ROM code can boot up using eMMC/SD devices:  through either two of the raw (boot, UDA) partitions, or through a file system such as FAT12/16/32.  All of these modes are supported by DRA72x, and can be used in mass production systems.  For more details, please refer to Section 32.3.7.6 eMMC Memories and SD cards of the TRM.

    Raw (Boot) mode offers the advantage of an optimized boot time by skipping over the regular MMC/SD identification phase, which is usually done at a slower speed.  This mode is also known as Alternate Boot Operation and can only be executed on eMMC.  While there is only one copy of boot image available in Raw (Boot) mode, there can be up to four copies in Raw (UDA) mode, which makes the latter beneficial during bad blocks encounter.  Raw (UDA) boot mode is not limited to eMMC usage and can be used with SD cards as well.

    FAT file system offers the advantage to quickly update boot images through the PC.  It also facilitates testing the same image on multiple different systems since the SD cards are portable and the images do not have to be flashed into each board individually.  

    Have a great day!

    Best Regards,

    Shiou Mei

  • 0 in reply to Shiou Mei Huang
    TI__Expert 5010 points
    Thanks, Shiou Mei

    If the Fat system encountered bad blocks, What effect will it have？

    Best Regards,

    Fredy
  • 0 in reply to Fredy Zhang
    TI__Genius 10180 points

    Fredy,

    eMMC on chip logic will handle all bad blocks the same way irregardless of filesystem in use.  As a result the same logic (bad block  retirement and data movement) is applicable to FAT32, Linux, and Android.

    Best Regards,

    Shiou Mei