diff --git a/src/ec/hp/kbc1126/acpi/battery.asl b/src/ec/hp/kbc1126/acpi/battery.asl
index 003e58ba11..5a6e5dcc64 100644
--- a/src/ec/hp/kbc1126/acpi/battery.asl
+++ b/src/ec/hp/kbc1126/acpi/battery.asl
@@ -230,7 +230,7 @@ Method (\ISTR, 2, Serialized)
 	{
 		Local1--
 		Divide (Local0, 10, Local2, Local0)
-		Add (Local2, 48, Index (NUMB, Local1))
+		Add (Local2, 48, NUMB[Local1])
 	}
 	ToString (NUMB, Arg1, Local3)
 	Return (Local3)