diff --git a/Makefile_kaldi2.cpu b/Makefile_kaldi2.cpu
index 5634bc954..e9d1757c0 100644
--- a/Makefile_kaldi2.cpu
+++ b/Makefile_kaldi2.cpu
@@ -25,6 +25,15 @@
 # export LD_LIBRARY_PATH=/usr/local/acml5.3.0/gfortran64/lib:/usr/local/cuda/lib64:/usr/local/lib
 # export PATH=$PATH:/usr/local/bin:/usr/local/cuda/bin
 
+# WARNING:
+# Since we now compile against Kaldi lattices, which depend on OpenFst, you
+# will have to re-compile Kaldi with OpenFst 1.4.1 (lower version of OpenFst
+# does not support c++11). You can do the following:
+# 1. In kaldi-trunk/tools/Makefile, uncomment # OPENFST_VERSION = 1.4.1, and
+#    re-install OpenFst using the makefile.
+# 2. In kaldi-trunk/src/, do ./configure --shared; make depend -j 8; make -j 8;
+#    and re-compile Kaldi.
+
 CC = g++-4.8
 ARCH = x86_64
 DEVICE = cpu