diff --git a/src/mainboard/system76/lemp9/devicetree.cb b/src/mainboard/system76/lemp9/devicetree.cb
index 7a6ba6a959..f3ae03a3e2 100644
--- a/src/mainboard/system76/lemp9/devicetree.cb
+++ b/src/mainboard/system76/lemp9/devicetree.cb
@@ -143,6 +143,9 @@ chip soc/intel/cannonlake
 	# Thermal
 	register "tcc_offset" = "12"
 
+	# Serial IRQ Continuous
+	register "SerialIrqConfigSirqMode" = "1"
+
 # LPC (soc/intel/cannonlake/lpc.c)
 	# LPC configuration from lspci -s 1f.0 -xxx
 	# Address 0x84: Decode 0x80 - 0x8F