SK-AM64B: Compatibility of microSD cards

Dhruva Kashyap

Part Number: SK-AM64B
Other Parts Discussed in Thread: TMDS64EVM

Tool/software:

Hello!

I've been having issues booting the SK-AM64B with RT Linux image downloaded from here: https://dr-download.ti.com/software-development/software-development-kit-sdk/MD-InmvA50mCw/11.00.09.04/tisdk-default-image-rt-am64xx-evm-11.00.09.04.rootfs.wic.xz, with microSD card being flashed using balenaEtcher on Windows.

Boot mode switches have been set as per the EVM quick start guide.

However, when using certain microSD cards, the kernel does not start. Here's the boot log:

U-Boot SPL 2025.01-00406-gcd91d7360181 (Mar 25 2025 - 16:14:37 +0000)
Resetting on cold boot to workaround ErrataID:i2331
Please resend tiboot3.bin in case of UART/DFU boot
resetting ...

U-Boot SPL 2025.01-00406-gcd91d7360181 (Mar 25 2025 - 16:14:37 +0000)
SYSFW ABI: 4.0 (firmware rev 0x000b '11.0.7--v11.00.07 (Fancy Rat)')
EEPROM not available at 0x50, trying to read at 0x51
SPL initial stack usage: 13392 bytes
Trying to boot from MMC2
Authentication passed
Authentication passed
Loading Environment from nowhere... OK
Authentication passed
Authentication passed
Starting ATF on ARM64 core...

NOTICE:  BL31: v2.12.0(release):11.00.08-1-gb11beb2b6-dirty
NOTICE:  BL31: Built : 12:35:58, Mar 24 2025
I/TC:
I/TC: OP-TEE version: 4.5.0-73-gef1ebdc23-dev (gcc version 13.3.0 (GCC)) #1 Tue Feb  4 11:33:18 UTC 2025 aarch64
I/TC: WARNING: This OP-TEE configuration might be insecure!
I/TC: WARNING: Please check https://optee.readthedocs.io/en/latest/architecture/porting_guidelines.html
I/TC: Primary CPU initializing
I/TC: GIC redistributor base address not provided
I/TC: Assuming default GIC group status and modifier
I/TC: SYSFW ABI: 4.0 (firmware rev 0x000b '11.0.7--v11.00.07 (Fancy Rat)')
I/TC: Activated SA2UL device
I/TC: Enabled firewalls for SA2UL TRNG device
I/TC: SA2UL TRNG initialized
I/TC: SA2UL Drivers initialized
I/TC: HUK Initialized
I/TC: Primary CPU switching to normal world boot

U-Boot SPL 2025.01-00406-gcd91d7360181 (Mar 25 2025 - 16:14:37 +0000)
SYSFW ABI: 4.0 (firmware rev 0x000b '11.0.7--v11.00.07 (Fancy Rat)')
Trying to boot from MMC2
spl: mmc init failed with error: -110
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

There have been a number of other E2E threads with similar issues, but none of them have definitively concluded on which category of microSD cards are supported.

SK-AM64: Bootable Linux SD-Card image: Tried using different cards and got the EVM to boot on the 4th card. No information on why the first three didn't work.

SK-AM64: SD Boot suggests using SDHC cards with 'C' class instead of 'U' class.

However, the EVM booted up using this card:

Note: This card has both 'C' and 'U' class categories.

And the EVM did not boot up with this card:

Note: Once again, this card has both 'C' and 'U' class categories, the only difference is the capacity.

What exactly defines whether a card is compatible or not?

Best regards,

Dhruva

3 months ago

0 Bin Liu 3 months ago

TI__Guru**** 168311 points

Hi Dhruva,

I am routing your query to our MMC expert for comments.

0 Jim Mrowca 3 months ago in reply to Bin Liu

Genius 4132 points

Guys: we also know about some resistors that need to be populated on the SK-AM64B due to some SD card manufacturers handling some lines not so well:

see AM64x SK EVM User's Guide (Rev. B) section 5.7 Issue 7 - uSD Boot Not Working

Given how many uSD card suppliers are out there (try to look at Amazon) - it can be hard to test & catalog every supplier and uSD type.

later

Jim

0 Prashant Shivhare 3 months ago

TI__Guru 70231 points

Hello,

For the non-working SD cards, you may try the following workarounds:

https://software-dl.ti.com/processor-sdk-linux/esd/AM64X/11_00_09_04/exports/docs/linux/Foundational_Components/U-Boot/UG-Memory-K3.html#steps-for-working-around-sd-card-issues-in-u-boot

Regards,

Prashant

0 MK 3 months ago in reply to Prashant Shivhare

TI__Intellectual 1650 points

Hi Prashant,

Can you recommend any particular SD card which will 100% work? We want to make it easier for the customer and not tedious.

Best Regards,

Madhurya

0 Prashant Shivhare 3 months ago in reply to MK

TI__Guru 70231 points

MK said:
Can you recommend any particular SD card which will 100% work? We want to make it easier for the customer and not tedious.

For the SK-AB64B case, nothing concrete can be said due to the issue described in the datasheet. Generally, the Samsung and even the Sandisk 64GB SD cards have been known to work well.

0 Dhruva Kashyap 3 months ago in reply to Prashant Shivhare

TI__Prodigy 20 points

Hi Prashant

According to this E2E SK-AM64: SD Boot - Processors forum - Processors - TI E2E support forums "The moral of the story: USE SDHC SDs! Not SDXC."

Since you recommended 64GB SD Cards which are usually the SDXC variant not SDHC (Source: What is the difference between SDUC, SDXC, SDHC and SD cards? | Integral Memory), should we recommend this to the customer?

0 Prashant Shivhare 3 months ago in reply to Dhruva Kashyap

TI__Guru 70231 points

Dhruva Kashyap said:
"The moral of the story: USE SDHC SDs! Not SDXC."

Well, I have Samsung EVO Plus 64GB SDXC card which boots successfully so it may not be about SDHC vs SDXC cards. The issue, for unknown reasons, is just with certain SD cards particularly the Sandisk Red 32GB card which has been known to fail across devices from different family.

Just try different SD cards and stick with the working ones. For the non-working ones, the previously shared workarounds can be applied!!

0 Jim Mrowca 3 months ago in reply to Dhruva Kashyap

Genius 4132 points

Dhruva:

TI should not & will not endorse any specific vendor or type of microSD cards. On top of that it would be a huge task for TI to even catalog all the microSD cards that can be used (the microSD card industry is changing every 2 years or so, with new tech).

All of the TMDS64EVM boards that TI sells ship with a bloack16GB SanDisk HC card. [That size is really hard to find at many suppliers & I tend to agree with Prashant mentioning a 64GB microSD card].

For what it's worth, one of the 3rd party AM64x SOM suppliers ship with a silver Transcend microSD card, which works for them.