Re: [PATCH] arm64:?==?utf-8?q? dts: rockchip: fix eMMC corruption on NanoPC-T6 with A3A444 chips

[Dragan Simic]

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).

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.

[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";
>  };