[PATCH] arm64: dts: rockchip: fix eMMC corruption on NanoPC-T6 with A3A444 chips

[Tianling Shen]

Hi Dragan,

On 2025/10/17 18:25, Dragan Simic wrote:
> Hello Tianling,
> 
> On Friday, October 17, 2025 09:39 CEST, Tianling Shen <cnsztl at gmail.com> wrote:
>> From: Grzegorz Sterniczuk <grzegorz at sternicz.uk>
>>
>> Some NanoPC-T6 boards with A3A444 eMMC chips experience I/O errors and
>> corruption when using HS400 mode. Downgrade to HS200 mode to ensure
>> stable operation.
> 
> Could you, please, provide more details about the troublesome eMMC
> chip that gets identified as A3A444, i.e. what's the actual brand
> and model?  Maybe you could send a picture of it?  It might also
> help if you'd send the contents of "/sys/class/block/mmcblkX/device
> /manfid" from your board (where "X" should equal two).

Unfortunately I don't have this board nor this eMMC chip.
I got the chip model from my friend, it's FORESEE FEMDNN256G-A3A44, 
manfid is 0x0000d6.

> 
> I'm asking for that because I'd like to research it a bit further,
> if possible, because some other eMMC chips that are also found on
> the NanoPc-T6 seem to work fine in HS400 mode. [1]  It may be that
> the A3A444 chip has some issues with the HS400 mode on its own,
> i.e. the observed issues may not be caused by the board.

Yes, it should be caused by this eMMC chip.

Thanks,
Tianling.

> 
> [1] https://github.com/openwrt/openwrt/issues/18844
> 
>> Signed-off-by: Grzegorz Sterniczuk <grzegorz at sternicz.uk>
>> Signed-off-by: Tianling Shen <cnsztl at gmail.com>
>> ---
>>   arch/arm64/boot/dts/rockchip/rk3588-nanopc-t6.dtsi | 3 +--
>>   1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/rockchip/rk3588-nanopc-t6.dtsi b/arch/arm64/boot/dts/rockchip/rk3588-nanopc-t6.dtsi
>> index fafeabe9adf9..5f63f38f7326 100644
>> --- a/arch/arm64/boot/dts/rockchip/rk3588-nanopc-t6.dtsi
>> +++ b/arch/arm64/boot/dts/rockchip/rk3588-nanopc-t6.dtsi
>> @@ -717,8 +717,7 @@ &sdhci {
>>   	no-sd;
>>   	non-removable;
>>   	max-frequency = <200000000>;
>> -	mmc-hs400-1_8v;
>> -	mmc-hs400-enhanced-strobe;
>> +	mmc-hs200-1_8v;
>>   	status = "okay";
>>   };
>