diff --git a/src/mainboard/system76/lemp9/devicetree.cb b/src/mainboard/system76/lemp9/devicetree.cb
index f0cee063e7..6bece6d047 100644
--- a/src/mainboard/system76/lemp9/devicetree.cb
+++ b/src/mainboard/system76/lemp9/devicetree.cb
@@ -178,7 +178,9 @@ chip soc/intel/cannonlake
 			register "SataMode" = "Sata_AHCI"
 			register "SataSalpSupport" = "0"
 			register "SataPortsEnable[1]" = "1"
+			register "SataPortsDevSlp[1]" = "1"
 			register "SataPortsEnable[2]" = "1"
+			register "SataPortsDevSlp[2]" = "1"
 		end
 		device pci 19.0 off end # I2C #4
 		device pci 19.1 off end # I2C #5