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Original question:

66AK2G12: MMCSD Boot Questions

66AK2G12: 66AK2G12: MMCSD Boot Questions 2

Bernhard Seiz
Intellectual 450 points
Part Number: 66AK2G12

Dear All,

sorry to not follow/aswer the already locked thread.

According to the linked thread i have a quesiton:

Is the chapter 33.3.76 of

AM572x
SitaraTM Processors
Silicon Revision 2.0, 1.1
Texas Instruments SitaraTM Family of Products
Technical Reference Manual

Literature Number: SPRUHZ6L
October 2014 – Revised August 2019

also appicable for boot process of the 66AK2G12 device?
Or does it differ in same aspects?

Bernhard

  • 0
    TI__Guru**** 161600 points

    Hi Bernhard,

    No, 66AK2G12 devices have their own TRM:

    You can check Chapter 4 Initialization for the supported boot modes & the boot flow of the SoC.

    Best Regards,
    Yordan

  • 0 in reply to Yordan Kovachev
    Intellectual 450 points

    Dear Yordan,

    thank you for your reply!

    Maybe I was not precise enough about my request. Sorry for that.

    Yes, of course I know about the 66AK2G12 specific TRM.

    My interest is especially on the layout and organisation of the boot-medium and the RBL behaviour. 

    Background: Our custom board is booting from SD card. Now we want to move to the internal eMMC.

    I am not sure about how to setup the eMMC.

    The AM572x TRM is very precise in the description of the RBL behaviour and the SD card/eMMC sector layout.

    In contrast the 66AK2G12 TRM does not describe anything about. Therefore the question about the other TRM.

    What I understand so far for the AM572X RBL is that it is no matter whether a MBR is available on the eMMC or not, it is able to boot MLO.

    The question is: Is the 66AK2G12 RBL behaving the same when booting from eMMC/SD card?

    Is it also 

    • trying to boot from boot sector
    • trying to boot from user space
    • booting with MBR
    • booting without MBR

    ?

    I would try the following boot setup now:

    • boot mode: mmcsd, emmc boot sector not used, no boot ack expected
    • setup a FatFs partition with MBR

    You think it should work like this?

    Thank you for your patience!

    Bernhard

  • 0 in reply to Bernhard Seiz
    Intellectual 450 points

    Dear All,

    I was able to setup a FatFs partition with MBR on the eMMC chip. 

    Missing point of FatFs was to create a bootable partition by writing 0x80 at the first position of the partition entry of the MBR. This made the partition bootable.

    The RBL is able to load the MLO i put into the eMMC drive.

    Next step for is to modify the modified MLO to load app from eMMC instead of SD card.

    Bernhard