From: Simon Glass <simon.glass@canonical.com> The Firefly-RK3399 board does not boot reliably in the SJG lab due to signal-integrity issues with SD-wire adapters at higher speeds. Reduce the SDMMC max-frequency to 25MHz and disable high-speed modes to improve compatibility. Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com> Signed-off-by: Simon Glass <simon.glass@canonical.com> --- arch/arm/dts/rk3399-firefly-u-boot.dtsi | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/dts/rk3399-firefly-u-boot.dtsi b/arch/arm/dts/rk3399-firefly-u-boot.dtsi index 1f5fda1d0f1..ca7a6694bcb 100644 --- a/arch/arm/dts/rk3399-firefly-u-boot.dtsi +++ b/arch/arm/dts/rk3399-firefly-u-boot.dtsi @@ -6,6 +6,12 @@ #include "rk3399-u-boot.dtsi" #include "rk3399-sdram-ddr3-1600.dtsi" +&sdmmc { + max-frequency = <25000000>; /* 25MHz for SD-wire compatibility */ + /delete-property/ cap-sd-highspeed; + /delete-property/ cap-mmc-highspeed; +}; + &vdd_log { regulator-init-microvolt = <950000>; }; -- 2.43.0