diff --git a/drivers/serial/serial_coreboot.c b/drivers/serial/serial_coreboot.c
index b1f69f6998c..89da11ffa52 100644
--- a/drivers/serial/serial_coreboot.c
+++ b/drivers/serial/serial_coreboot.c
@@ -59,7 +59,8 @@ static int read_dbg2(struct ns16550_plat *plat)
 		log_debug("Not a serial port\n");
 		return -EPROTOTYPE;
 	}
-	if (dbg->port_subtype != ACPI_DBG2_16550_COMPATIBLE) {
+	if (dbg->port_subtype != ACPI_DBG2_16550_COMPATIBLE &&
+	    dbg->port_subtype != ACPI_DBG2_16550_WITH_GAS) {
 		log_debug("Incompatible serial port\n");
 		return -EPROTOTYPE;
 	}
diff --git a/include/acpi/acpi_table.h b/include/acpi/acpi_table.h
index 4895366a618..ac50ea10312 100644
--- a/include/acpi/acpi_table.h
+++ b/include/acpi/acpi_table.h
@@ -674,6 +674,7 @@ struct __packed acpi_dmar {
 #define ACPI_DBG2_ARM_SBSA_GENERIC	0x000E
 #define ACPI_DBG2_ARM_DCC		0x000F
 #define ACPI_DBG2_BCM2835		0x0010
+#define ACPI_DBG2_16550_WITH_GAS	0x0012 /* 16550-compatible UART with GAS */
 
 #define ACPI_DBG2_1394_STANDARD		0x0000