diff --git a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
index 2a1cfd37e9..dcaab3eef2 100644
--- a/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
+++ b/arch/arm/dts/stm32mp157a-dk1-u-boot.dtsi
@@ -189,6 +189,8 @@
 	};
 	pins2 {
 		u-boot,dm-pre-reloc;
+		/* pull-up on rx to avoid floating level */
+		bias-pull-up;
 	};
 };
 
diff --git a/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi b/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi
index 200601edff..21c89c1ea2 100644
--- a/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi
+++ b/arch/arm/dts/stm32mp157c-ed1-u-boot.dtsi
@@ -206,5 +206,7 @@
 	};
 	pins2 {
 		u-boot,dm-pre-reloc;
+		/* pull-up on rx to avoid floating level */
+		bias-pull-up;
 	};
 };