[Buildroot] eMMC image not booting (uboot related issue)

Andy Bergh allmyaddmin at gmail.com
Sun May 2 07:47:34 UTC 2021


Hi Marko,

*Maybe a hint for you:*
>
> *- I think "mccdev" could be the wrong variable, the correct is "mmcdev"*
>
>
>  You are 100% correct. This was a typo I made. When I corrected it the OS
booted successfully.

Thank you very much!

On Fri, Apr 30, 2021 at 5:39 PM Marko Stanisic <sankerspace at gmail.com>
wrote:

>
> Hi Andy,
>
> Maybe a hint for you:
>
> - I think "mccdev" could be the wrong variable, the correct is "mmcdev"
>
>
> - In your output i saw following:
> On a working boot:
>
>
>
> *Hit any key to stop autoboot:  0 switch to partitions #0, OK mmc0 is
> current device SD/MMC found on device 0*
>
> Are you sure that mmcdev=1?
>
> Check it with following command :
>
>     => mmc list
>
> if it show something like:
>
>     FSL_SDHC: 0 (eMMC)
>
> than the correct setting can be changed with:
>
>     *=> setenv mmcdev 0*
>
> otherwise
>
>
> *=> setenv mmcdev 1 *
>
>
>
> - Regarding 2)  Boot from the SDCard and configure the eMMC using fdisk.
>
> these are two different device using the same bus, because they are both
> mmc devices, do you
>
> explicitly use the emmc of the beaglebone and you dont want the sd-card,
> could be confusing to understand.
>
> In case of the emmc:
>
> First, How about the fuse settings of the emmc?  Second, sdcard and emmc
> are bot mmc devices, maybe
>
> mmcdev=1 indicates the sd card. I dont have a beaglebone, but i would
> recommend to study the
>
> cpu documentation and beaglebone, these should give a solid hit how
> perfoirm a change between
>
> sdcard and emmc.
>
> You should also Overview the boot settings, maybe they are specialized to
> the sd-card case.
>
>
> Whish happy coding :)
>
>
> On 30.04.21 16:38, Andy Bergh wrote:
>
> Hi,
>
> Sorry to spam. I managed to set the mccdev var to 1 before booting but it
> still fails (using the preboot option in uboot-menuconfig). So that was not
> the issue. The output and error:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> *Hit any key to stop autoboot:  0 => printenv mccdev mccdev=1 => boot
> switch to partitions #0, OK mmc1(part 0) is current device Scanning mmc
> 1:1... 40817 bytes read in 4 ms (9.7 MiB/s) switch to partitions #0, OK
> mmc1(part 0) is current device SD/MMC found on device 1 ## Error:
> "bootcmd_nand0" not defined starting USB... Bus usb at 47401800: Port not
> available. link up on port 0, speed 100, full duplex BOOTP broadcast 1
> BOOTP broadcast 2*
>
> On a working boot:
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> *Hit any key to stop autoboot:  0 switch to partitions #0, OK mmc0 is
> current device SD/MMC found on device 0 591 bytes read in 2 ms (288.1
> KiB/s) Loaded env from uEnv.txt Importing environment from mmc0 ... Running
> uenvcmd ... 6090656 bytes read in 392 ms (14.8 MiB/s) 40817 bytes read in 5
> ms (7.8 MiB/s) bootargs=console=ttyS0,115200n8 root=/dev/mmcblk0p2 rw
> rootfstype=ext4 rootwait ## Flattened Device Tree blob at 88000000
>  Booting using the fdt blob at 0x88000000    Loading Device Tree to
> 8fff3000, end 8fffff70 ... OK *
> *Starting kernel ...*
>
> I truly am stuck here. Any advice would be appreciated.
>
> Thank you
>
>
> On Fri, Apr 30, 2021 at 3:02 PM Andy Bergh <allmyaddmin at gmail.com> wrote:
>
>> Hi,
>>
>> I have made an image for my Beaglebone Black using buildroot, great
>> project, thanks. The sdcard.img boots fine, but I can not get it to boot
>> from power up from the eMMC.
>>
>> What I have done:
>> 1) Build an image using buildroot (with beaglebone_defconfig).
>> The sdcard.img boots just fine.
>> 2) Boot from the SDCard and configure the eMMC using fdisk. I followed
>> the instructions shown here
>> <https://e2e.ti.com/support/processors/f/processors-forum/344528/u-boot-write-mlo-uboot-uimage-rootfs-on-to-emmc-mnand-of-am335x-evm-j5-echo-based-custom-board/1204926#1204926>
>> .
>>
>> Once the eMMC is configured I perform a power cycle at which point the
>> boot fails. I end up at the uboot prompt (UART port), if I then type "boot"
>> the OS boots correctly.
>> What I have noticed is that the variable mmcdev is set to 0 at startup.
>> After it has failed if I do another printenv mmcdev and then it is set to 1.
>>
>> I suspect this is the reason it does not boot successfully at power up,
>> but I may be very wrong!
>>
>> How can I set the env var mccdev to be 1 as default at startup? Is this
>> possible, perhaps with uboot-menuconfig? Is that the correct way to solve
>> this problem?
>>
>> Any information would be much appreciated.
>>
>> Thank you
>>
>
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