AM62A7: SD Boot issue

Hello,

The Subject Matter Expert will get back to you with a response next week. Thank you for your patience.

Hi @Anshu Madwesh,

Is there any update in this case?

Regards,
Sushmitha K

Hi Sushmitha,

Could you share how are the boot mode switches set on the EVM? 
What is the primary and secondary boot mode?

U-boot will load files from SD card by default. There might be changes in the environment variables for this to happen.

Can you share the output of following commands at U-boot prompt?

=> printenv mmcdev
=> printenv bootpart

Hi @Aparna Patra,

We are using custom board with eMMC as primary and SD as secondary boot loader.
> printenv mmcdev                                                                           
mmcdev=1
> printenv bootpart
bootpart=0:2

Regards,
Sushmitha K

Hi Sushmitha,

If you want to boot from SD card completely, there should be the following variables set:

=> printenv mmcdev
mmcdev=1
=> printenv bootpart
bootpart=1:2

Use the following commands to set them respectively:

=> setenv mmcdev 1
=> setenv bootpart 1:2
=> saveenv

Hi @Aparna Patra,

We have tried with the command given but still kernel and file system is booting from eMMC.

This is because the PARTUUID is same for SD and eMMC. Because of this while booting from SD, Kernel and filesystem is booted from eMMC.


Regards,
Sushmitha K

Could you try partitioning the EMMC once again, the instructions are documented here: https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/09_01_00_08/exports/docs/linux/Foundational_Components/U-Boot/UG-Memory.html#partitioning-emmc-from-u-boot

Regards,
Aparna

Hi Apartna Patra,

Checked the given link and followed the same procedure.

But still we are unable to boot from SD.

The PARTUUID is same for emmC and SD. So manually i have changed the PARTUUID for SD so that it is booting completely from SD.

Regards,
Sushmitha K

Hi Sushmitha,

Sushmitha K said:

So manually i have changed the PARTUUID for SD so that it is booting completely from SD

I need some clarification here. Do you mean it is booting from SD now, when you have changed the PARTUUID?

Regards,
Aparna

Hi Aparna Patra,

With fdisk command i have changed the PARTUUID for SD

Regards,
Sushmitha K

Hi Sushmitha,

Is the issue resolved then?

Regards,
Aparna

Hi Aparna Patra,

Instead of giving root=PARTUUID=${uuid} , can give the MMC dev number from which it is booting ?

Can you try in your board by flashing same rootfs.wic to both emmc and SD whether it boots if you specify root=PARTUUID=${uuid} ?

Regards,
Sushmitha K

Hi Sushmitha,

Sorry for delayed response!

I will try this and update in sometime.

Regards,
Aparna

Hi Aparna Patra,

Is there any update in  this case?

Regards,
Sushmitha K

Hi Sushmitha,

I can see the same behaviour at my end.

Can you try the following changes, re-build the images, flash it into SD card:

diff --git a/include/environment/ti/mmc.env b/include/environment/ti/mmc.env
index 1e62bf85..b33c4034 100644
--- a/include/environment/ti/mmc.env
+++ b/include/environment/ti/mmc.env
@@ -3,7 +3,7 @@ mmcrootfstype=ext4 rootwait
 finduuid=part uuid ${boot} ${bootpart} uuid
 args_mmc=run finduuid;setenv bootargs console=${console}
     ${optargs}
-    root=PARTUUID=${uuid} rw
+    root=/dev/mmcblk1p2 rw
     rootfstype=${mmcrootfstype}
 loadbootscript=load mmc ${mmcdev} ${loadaddr} boot.scr
 bootscript=echo Running bootscript from mmc${mmcdev} ...;
``