diff --git a/pkgs/development/python-modules/kaldi-active-grammar/fork.nix b/pkgs/development/python-modules/kaldi-active-grammar/fork.nix
index 8f5a11f14c61c..7748e34df6f2d 100644
--- a/pkgs/development/python-modules/kaldi-active-grammar/fork.nix
+++ b/pkgs/development/python-modules/kaldi-active-grammar/fork.nix
@@ -13,15 +13,19 @@
 }:
 
 let
-  old-openfst = openfst.overrideAttrs (self: {
+  old-openfst = openfst.overrideAttrs (prev: {
+    version = "kag-unstable-2022-05-06";
+
     src = fetchFromGitHub {
       owner = "kkm000";
       repo = "openfst";
+      # required by https://github.com/daanzu/kaldi-fork-active-grammar/blob/e9c7d0ffca401cf312779d25f2c05a34b41ff696/cmake/third_party/openfst.cmake#L7
       rev = "0bca6e76d24647427356dc242b0adbf3b5f1a8d9";
       sha256 = "1802rr14a03zl1wa5a0x1fa412kcvbgprgkadfj5s6s3agnn11rx";
     };
     buildInputs = [ zlib ];
-  }); in
+  });
+in
 
 assert blas.implementation == "openblas" && lapack.implementation == "openblas";
 
@@ -66,6 +70,20 @@ stdenv.mkDerivation rec {
   postPatch = ''
     # Replace the shebangs for the various build scripts
     patchShebangs src
+    # Compatability with OpenBLAS 0.3.21
+    substituteInPlace src/matrix/cblas-wrappers.h \
+      --replace stptri_ LAPACK_stptri \
+      --replace dtptri_ LAPACK_dtptri \
+      --replace sgetrf_ LAPACK_sgetrf \
+      --replace dgetrf_ LAPACK_dgetrf \
+      --replace sgetri_ LAPACK_sgetri \
+      --replace dgetri_ LAPACK_dgetri \
+      --replace sgesvd_ LAPACK_sgesvd \
+      --replace dgesvd_ LAPACK_dgesvd \
+      --replace ssptri_ LAPACK_ssptri \
+      --replace dsptri_ LAPACK_dsptri \
+      --replace ssptrf_ LAPACK_ssptrf \
+      --replace dsptrf_ LAPACK_dsptrf
   '';
 
   configurePhase = ''