diff --git a/pkgs/development/coq-modules/fiat/HEAD.nix b/pkgs/development/coq-modules/fiat/HEAD.nix
index bc5c0fdd6bb7..b970747c7726 100644
--- a/pkgs/development/coq-modules/fiat/HEAD.nix
+++ b/pkgs/development/coq-modules/fiat/HEAD.nix
@@ -1,23 +1,22 @@
-{stdenv, fetchgit, coq, ocamlPackages, python27}:
+{stdenv, fetchgit, coq, python27}:
 
 stdenv.mkDerivation rec {
 
   name = "coq-fiat-${coq.coq-version}-unstable-${version}";
-  version = "2018-02-27";
+  version = "2016-10-24";
 
   src = fetchgit {
     url = "https://github.com/mit-plv/fiat.git";
-    rev = "253fc133397f73d6daed0b9518ca7ab5507a1cb0";
-    sha256 = "0b5z7nz0cr1s7vy04s996dj0pd7ljqx6g5a8syh4hy2z87ijkjzd";
+    rev = "7feb6c64be9ebcc05924ec58fe1463e73ec8206a";
+    sha256 = "0griqc675yylf9rvadlfsabz41qy5f5idya30p5rv6ysiakxya64";
   };
 
-  buildInputs = [ ocamlPackages.ocaml ocamlPackages.camlp5_transitional
-                  ocamlPackages.findlib python27 ];
+  buildInputs = [ coq.ocaml coq.camlp5 python27 ];
   propagatedBuildInputs = [ coq ];
 
   doCheck = false;
 
-  enableParallelBuilding = true;
+  enableParallelBuilding = false;
   buildPhase = "make -j$NIX_BUILD_CORES";
 
   installPhase = ''
@@ -34,6 +33,6 @@ stdenv.mkDerivation rec {
   };
 
   passthru = {
-    compatibleCoqVersions = v: builtins.elem v [ "8.5" "8.6" "8.7" ];
+    compatibleCoqVersions = v: v == "8.5";
   };
 }