diff --git a/util/autoport/readme.md b/util/autoport/readme.md
index cfa8c36a38..fa349b906f 100644
--- a/util/autoport/readme.md
+++ b/util/autoport/readme.md
@@ -268,6 +268,12 @@ If several slots are soldered there are two ways to handle them:
   not forget to copy the data on all the array elements that need it.
 * If they use different data, use several files.
 
+If memory initialization is not working, in particular write training (timB)
+on DIMM's second rank fails, try enbling rank 1 mirroring, which can't be
+detected by inteltool. It is described by SPD field "Address Mapping from Edge
+Connector to DRAM", byte `63` (`0x3f`). Bit 0 describes Rank 1 Mapping,
+0 = standard, 1 = mirrored; set it to 1. Bits 1-7 are reserved.
+
 ### `board_info.txt`
 
 `board_info.txt` is a text file used in the board status page to list all