diff --git a/soc/st/stm32/stm32u3x/Kconfig.defconfig b/soc/st/stm32/stm32u3x/Kconfig.defconfig
index bcc32a88ddb..c5914a05bb3 100644
--- a/soc/st/stm32/stm32u3x/Kconfig.defconfig
+++ b/soc/st/stm32/stm32u3x/Kconfig.defconfig
@@ -8,4 +8,7 @@ if SOC_SERIES_STM32U3X
 config NUM_IRQS
 	default 125
 
+config ROM_START_OFFSET
+	default 0x400 if BOOTLOADER_MCUBOOT
+
 endif # SOC_SERIES_STM32U3X