diff --git a/src/include/acpi/acpi.h b/src/include/acpi/acpi.h
index 9a9a66d50b..a26d735865 100644
--- a/src/include/acpi/acpi.h
+++ b/src/include/acpi/acpi.h
@@ -866,12 +866,13 @@ typedef struct acpi_gic_its {
 _Static_assert(sizeof(acpi_madt_gic_its_t) == 20, "Wrong MADT acpi_madt_gic_its_t size\n");
 
 #define ACPI_DBG2_PORT_SERIAL			0x8000
-#define  ACPI_DBG2_PORT_SERIAL_16550		0x0000
+#define  ACPI_DBG2_PORT_SERIAL_16550_IO_ONLY	0x0000
 #define  ACPI_DBG2_PORT_SERIAL_16550_DBGP	0x0001
 #define  ACPI_DBG2_PORT_SERIAL_ARM_PL011	0x0003
 #define  ACPI_DBG2_PORT_SERIAL_ARM_SBSA		0x000e
 #define  ACPI_DBG2_PORT_SERIAL_ARM_DDC		0x000f
 #define  ACPI_DBG2_PORT_SERIAL_BCM2835		0x0010
+#define  ACPI_DBG2_PORT_SERIAL_16550		0x0012
 #define ACPI_DBG2_PORT_IEEE1394			0x8001
 #define  ACPI_DBG2_PORT_IEEE1394_STANDARD	0x0000
 #define ACPI_DBG2_PORT_USB			0x8002