diff --git a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
index 002ece51c3baa86c482a094bfa1556040403fd03..08fa00364b42f0f4a509cf0c5613ebd79fe56a9d 100644
--- a/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3399-puma.dtsi
@@ -439,6 +439,12 @@
 };
 
 &sdhci {
+	/*
+	 * Signal integrity isn't great at 200MHz but 100MHz has proven stable
+	 * enough.
+	 */
+	max-frequency = <100000000>;
+
 	bus-width = <8>;
 	mmc-hs400-1_8v;
 	mmc-hs400-enhanced-strobe;