diff --git a/target/linux/ramips/dts/mt7621.dtsi b/target/linux/ramips/dts/mt7621.dtsi
index 033ba95dd7..da992bada4 100644
--- a/target/linux/ramips/dts/mt7621.dtsi
+++ b/target/linux/ramips/dts/mt7621.dtsi
@@ -365,7 +365,7 @@
 		interrupt-parent = <&gic>;
 		interrupts = <GIC_SHARED 20 IRQ_TYPE_LEVEL_HIGH>;
 
-		max-frequency = <50000000>;
+		max-frequency = <48000000>;
 
 		pinctrl-names = "default", "state_uhs";
 		pinctrl-0 = <&sdhci_pins>;