diff --git a/arch/arm/soc/nxp_kinetis/k6x/Kconfig.defconfig.mk64f12 b/arch/arm/soc/nxp_kinetis/k6x/Kconfig.defconfig.mk64f12
index edaea08ad41..ba8b12d737c 100644
--- a/arch/arm/soc/nxp_kinetis/k6x/Kconfig.defconfig.mk64f12
+++ b/arch/arm/soc/nxp_kinetis/k6x/Kconfig.defconfig.mk64f12
@@ -74,4 +74,11 @@ config SOC_FLASH_MCUX
 
 endif # FLASH
 
+if SERIAL
+
+config UART_MCUX
+	def_bool y
+
+endif # SERIAL
+
 endif # SOC_MK64F12
diff --git a/boards/arm/frdm_k64f/frdm_k64f_defconfig b/boards/arm/frdm_k64f/frdm_k64f_defconfig
index 3f738f04195..6c1d8a7f91d 100644
--- a/boards/arm/frdm_k64f/frdm_k64f_defconfig
+++ b/boards/arm/frdm_k64f/frdm_k64f_defconfig
@@ -6,7 +6,6 @@ CONFIG_CONSOLE=y
 CONFIG_UART_CONSOLE=y
 CONFIG_SERIAL=y
 CONFIG_CORTEX_M_SYSTICK=y
-CONFIG_UART_K20=y
 CONFIG_GPIO=y
 CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=120000000
 CONFIG_OSC_EXTERNAL=y
diff --git a/boards/arm/hexiwear_k64/hexiwear_k64_defconfig b/boards/arm/hexiwear_k64/hexiwear_k64_defconfig
index 70e7dde98bd..7501e33b1ee 100644
--- a/boards/arm/hexiwear_k64/hexiwear_k64_defconfig
+++ b/boards/arm/hexiwear_k64/hexiwear_k64_defconfig
@@ -6,7 +6,6 @@ CONFIG_CONSOLE=y
 CONFIG_UART_CONSOLE=y
 CONFIG_SERIAL=y
 CONFIG_CORTEX_M_SYSTICK=y
-CONFIG_UART_K20=y
 CONFIG_GPIO=y
 CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC=120000000
 CONFIG_OSC_LOW_POWER=y