diff --git a/techlibs/ice40/lut.lut b/techlibs/ice40/lut.lut
index 6fa0682da..eef997869 100644
--- a/techlibs/ice40/lut.lut
+++ b/techlibs/ice40/lut.lut
@@ -1,6 +1,6 @@
 # From https://github.com/cliffordwolf/icestorm/blob/81c33a3/icefuzz/timings_hx8k.txt
-
-1	1	316
-2	1	316 379
-3	1	316 379 400
-4	1	316	379	400	449
+#       I3  I2  I1  I0
+1   1   316
+2   1   316 379
+3   1   316 379 400
+4   1   316 379 400 449