diff --git a/nix/ocaml-overlay.nix b/nix/ocaml-overlay.nix
index c750a9f27..93afa2dc4 100644
--- a/nix/ocaml-overlay.nix
+++ b/nix/ocaml-overlay.nix
@@ -22,6 +22,9 @@ in {
           macaddr = osuper.macaddr.versions."4.0.0";
           ocaml-migrate-parsetree = osuper.ocaml-migrate-parsetree.versions."1.4.0";
           ppx_tools_versioned = osuper.ppx_tools_versioned.versions."5.2.3";
+          menhir = osuper.menhir.versions."20190626".overrideAttrs (_: {
+            buildPhase = "make PREFIX=$out";
+          });
           tezos-protocol-compiler = osuper.tezos-protocol-compiler.overrideAttrs
             (oa: {
               buildInputs = oa.buildInputs ++ [ oself.pprint ];
@@ -81,153 +84,3 @@ in {
         })
     ]);
 }
-# (oself: osuper:
-#   let
-#     callTezosPackage = name: args:
-#       oself.callOPAMPackage "${sources.tezos}/src/lib_${
-#         builtins.replaceStrings [ "-" ] [ "_" ] name
-#       }" ({
-#         pname = "tezos-${name}";
-#         version = sources.tezos.rev;
-#       });
-#     tezos = builtins.listToAttrs (map (name: {
-#       name = "tezos-${name}";
-#       value = callTezosPackage name { } { };
-#     }) [
-#       "base"
-#       "event-logging"
-#       "micheline"
-#       "clic"
-#       "rpc"
-#       "error-monad"
-#       "stdlib"
-#       "crypto"
-#     ]);
-#   in tezos // {
-#     lwt = oself.lwt4;
-#     bigstring = oself.callOPAMPackage sources.bigstring {
-#       opamFile = "bigstring.opam";
-#       buildPhase = "dune build -p bigstring";
-#     } { bigstring-unix = null; };
-#     hidapi = oself.callOPAMPackage sources.hidapi {
-#       version = "1.1.1";
-#       extraBuildInputs = [ self.pkg-config ];
-#     } { conf-hidapi = self.hidapi; };
-#     crowbar = oself.callOPAMPackage sources.crowbar {
-#       pname = "crowbar";
-#       version = "0.1";
-#     } { };
-#     afl-persistent = oself.callOPAMPackage sources.ocaml-afl-persistent {
-#       pname = "afl-persistent";
-#       version = "1.1";
-#     } { };
-#     blake2 = oself.callOPAMPackage sources.blake2 {
-#       pname = "blake2";
-#       version = "0.2";
-#     } { };
-#     hacl = oself.callOPAMPackage sources.hacl {
-#       pname = "hacl";
-#       version = "0.1";
-#     } { };
-#     xmldiff = oself.callPackage
-#       ({ stdenv, autoreconfHook, ocaml, findlib, xmlm }:
-#         stdenv.mkDerivation {
-#           pname = "xmldiff";
-#           version = "0.5.0";
-#           src = sources.xmldiff;
-#           preInstall =
-#             "mkdir -p $out/lib/ocaml/${oself.ocaml.version}/site-lib";
-#           nativeBuildInputs = [ autoreconfHook ocaml findlib ];
-#           buildInputs = [ xmlm findlib ];
-#         }) { };
-#     json-data-encoding = oself.callOPAMPackage sources.json-data-encoding {
-#       opamFile = "json-data-encoding.opam";
-#       pname = "json-data-encoding";
-#       version = "0.8";
-#       extraBuildInputs = [ oself.crowbar ];
-#     } { };
-#     json-data-encoding-bson =
-#       oself.callOPAMPackage sources.json-data-encoding {
-#         opamFile = "json-data-encoding-bson.opam";
-#         pname = "json-data-encoding-bson";
-#         version = "0.8";
-#       } { };
-#     data-encoding = oself.callOPAMPackage sources.data-encoding {
-#       pname = "data-encoding";
-#       version = "0.0.0";
-#     } { };
-#     secp256k1-internal = oself.callOPAMPackage sources.secp256k1-internal {
-#       pname = "secp256k1-internal";
-#       version = "0.1.0";
-#     } { conf-gmp = self.gmp; };
-#     uecc = oself.callOPAMPackage sources.uecc {
-#       pname = "uecc";
-#       version = "0.1";
-#     } { };
-#     resto = oself.callOPAMPackage sources.resto {
-#       opamFile = "resto.opam";
-#       pname = "resto";
-#       version = "0.4";
-#     } { };
-#     resto-directory = oself.callOPAMPackage sources.resto {
-#       opamFile = "resto-directory.opam";
-#       pname = "resto-directory";
-#       version = "0.4";
-#     } { resto-json = null; };
-#     lwt-canceler = oself.callOPAMPackage sources.lwt-canceler {
-#       pname = "lwt-canceler";
-#       version = "0.2";
-#     } { };
-#     simple-utils =
-#       oself.callOPAMPackage ../vendors/ligo-utils/simple-utils {
-#         pname = "simple-utils";
-#         version = "0.1";
-#       } { };
-#     michelson-parser = oself.callOPAMPackage
-#       ../vendors/ligo-utils/tezos-utils/michelson-parser {
-#         pname = "michelson-parser";
-#         version = "0.0.0";
-#       } { ocamlfind = oself.findlib; };
-#     tezos-tooling = oself.callOPAMPackage "${sources.tezos}/src/tooling" {
-#       pname = "tezos-tooling";
-#       version = sources.tezos.rev;
-#     } { };
-#     tezos-protocol-environment = oself.callOPAMPackage
-#       "${sources.tezos}/src/lib_protocol_environment" {
-#         pname = "tezos-protocol-environment";
-#         opamFile = "tezos-protocol-environment.opam";
-#         version = sources.tezos.rev;
-#       } { };
-#     tezos-memory-proto-alpha =
-#       oself.callOPAMPackage ../vendors/ligo-utils/memory-proto-alpha {
-#         pname = "tezos-memory-proto-alpha";
-#         version = "0.0.0";
-#       } { };
-#     tezos-stdlib-unix =
-#       oself.callOPAMPackage "${sources.tezos}/src/lib_stdlib_unix" {
-#         pname = "tezos-stdlib-unix";
-#         version = sources.tezos.rev;
-#         extraBuildInputs = [ oself.fmt ];
-#       } { conf-libev = self.libev; };
-#     tezos-protocol-alpha = null;
-#     tezos-protocol-006-PsCARTHA = null;
-#     tezos-protocol-environment-sigs = null;
-#     tezos-data-encoding = null;
-#     tezos-utils = oself.callOPAMPackage ../vendors/ligo-utils/tezos-utils {
-#       pname = "tezos-utils";
-#       version = "0.1";
-#     } { };
-#     proto-alpha-utils =
-#       oself.callOPAMPackage ../vendors/ligo-utils/proto-alpha-utils {
-#         pname = "proto-alpha-utils";
-#         version = "0.1";
-#       } { };
-#     terminal_size = oself.callOPAMPackage sources.terminal_size {
-#       pname = "terminal_size";
-#       version = "0.1.4";
-#     } { };
-#     ligo = oself.callOPAMPackage ../. { version = "0.1"; } {
-#       ocamlfind = oself.findlib;
-#     };
-#   });
-# }
diff --git a/nix/opam-parser.hs b/nix/opam-parser.hs
index 5c8cbd705..1dafb875f 100644
--- a/nix/opam-parser.hs
+++ b/nix/opam-parser.hs
@@ -37,6 +37,7 @@ opam2nix OPAM {..} =
     preparephase = mconcat . intersperse " " . mconcat . intersperse ["\n"]
   in
     "{ stdenv, fetchzip, " <>deps<> " }:\n"
+  <>"with {};\n" -- Awful hack to allow this to evaluate even if some of the variables are undefined
   <>"stdenv.mkDerivation rec {\n"
   <>foldMap (\name' -> "  pname = \""<>name'<>"\";\n") name
   <>foldMap (\version' -> "  version = \""<>version'<>"\";\n") version
@@ -112,6 +113,7 @@ evaluateExp :: Exp -> String
 evaluateExp =
   let
     repl ('%':'{':xs) = '$':'{':repl xs
+    repl ('}':'%':xs) = '}':repl xs
     repl (':':_:_:_:'}':'%':xs) = '}':repl xs
     repl (x:xs) = x:repl xs
     repl "" = ""
diff --git a/nix/sources.json b/nix/sources.json
index 48ba70104..8ef716141 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -1,100 +1,4 @@
 {
-    "UnionFind": {
-        "branch": "master",
-        "description": "Some variant implementations of the Union-Find algorithm",
-        "homepage": null,
-        "owner": "rinderknecht",
-        "repo": "UnionFind",
-        "rev": "97fdfa78a830e74fd3736e433152b662796840be",
-        "sha256": "0grsrv03x7r5azdcbcbsfdxq7myqnpr4wjgn14faxhnspkigcl9x",
-        "type": "tarball",
-        "url": "https://github.com/rinderknecht/UnionFind/archive/97fdfa78a830e74fd3736e433152b662796840be.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "bigstring": {
-        "branch": "master",
-        "description": "Overlay over bigarrays of chars",
-        "homepage": "http://c-cube.github.io/ocaml-bigstring/",
-        "owner": "c-cube",
-        "repo": "ocaml-bigstring",
-        "rev": "38f766741634bfeba3f24ca72d4e902289d1a75d",
-        "sha256": "1vxc8jaxxn2djiwa8p12my5a2q1w3j3cdcdsafx0mlw3sz601siy",
-        "type": "tarball",
-        "url": "https://github.com/c-cube/ocaml-bigstring/archive/38f766741634bfeba3f24ca72d4e902289d1a75d.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "blake2": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/ocaml-blake2",
-        "rev": "d9599805097ee70ab271ffebcf959683efad9aaa",
-        "type": "git"
-    },
-    "crowbar": {
-        "branch": "master",
-        "description": "Property fuzzing for OCaml",
-        "homepage": null,
-        "owner": "stedolan",
-        "repo": "crowbar",
-        "rev": "9bbb8013c41c632e15db639cdba8a0d180c9755f",
-        "sha256": "01d7qp1xg0vrm7xi7chzx7kfrbfh504hwmpz7s44rkwhrdp9dk9x",
-        "type": "tarball",
-        "url": "https://github.com/stedolan/crowbar/archive/9bbb8013c41c632e15db639cdba8a0d180c9755f.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "data-encoding": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/data-encoding",
-        "rev": "c38bfaf8d320e05050a55b7634503f5dd80d9668",
-        "type": "git"
-    },
-    "genspio": {
-        "branch": "master",
-        "description": "Generate Shell Phrases In OCaml",
-        "homepage": "https://smondet.gitlab.io/genspio-doc/",
-        "owner": "hammerlab",
-        "repo": "genspio",
-        "rev": "f270fb296cebcf25e2ea89a7929a274c03ae9e6e",
-        "sha256": "09kr2b78f2184fajavbi7zigy0zlhz0bys4679rg0h6p828rdfhq",
-        "type": "tarball",
-        "url": "https://github.com/hammerlab/genspio/archive/f270fb296cebcf25e2ea89a7929a274c03ae9e6e.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "hacl": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/ocaml-hacl",
-        "rev": "d2e39bb0c53188369723d97c48f1c50184544624",
-        "type": "git"
-    },
-    "hidapi": {
-        "branch": "master",
-        "description": "Bindings to http://www.signal11.us/oss/hidapi/",
-        "homepage": null,
-        "owner": "vbmithr",
-        "repo": "ocaml-hidapi",
-        "rev": "5ea3529099955b290199621b5e7b4cb74ffabf95",
-        "sha256": "1qhc8iby3i54zflbi3yrnhpg62pwdl6g2sfnykgashjy7ghh495y",
-        "type": "tarball",
-        "url": "https://github.com/vbmithr/ocaml-hidapi/archive/5ea3529099955b290199621b5e7b4cb74ffabf95.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "json-data-encoding": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/json-data-encoding",
-        "rev": "0112ce9e2b07ad7a77ac383e9a22261045dd0018",
-        "type": "git"
-    },
-    "ligo-utils": {
-        "ref": "master",
-        "repo": "https://gitlab.com/ligolang/ligo-utils",
-        "rev": "533c801c103627484af042bf1f976eeffcf592e3",
-        "type": "git"
-    },
-    "lwt-canceler": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/lwt-canceler",
-        "rev": "02e6e7cc23bf6ab9479bc370b1511a727ce02c61",
-        "type": "git"
-    },
     "nixpkgs": {
         "branch": "ocaml-cross-fixes",
         "description": "Pinned Nixpkgs tree (master follows nixos-unstable-small, only tags have stable history)",
@@ -107,18 +11,6 @@
         "url": "https://github.com/serokell/nixpkgs/archive/80a7615300badde924f2ca30caa988484c6c11cc.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
-    "ocaml-afl-persistent": {
-        "branch": "master",
-        "description": "persistent-mode afl-fuzz for ocaml",
-        "homepage": null,
-        "owner": "stedolan",
-        "repo": "ocaml-afl-persistent",
-        "rev": "a37c4f581ba417d7e09a6efb34fdd8a90a7e9ede",
-        "sha256": "1krp9vbyi79hh9nhylx47frsb08wb9vla85kykx5cma5y6rnxprh",
-        "type": "tarball",
-        "url": "https://github.com/stedolan/ocaml-afl-persistent/archive/a37c4f581ba417d7e09a6efb34fdd8a90a7e9ede.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
     "opam-repository": {
         "branch": "master",
         "description": "Main public package repository for OPAM, the source package manager of OCaml.",
@@ -131,48 +23,12 @@
         "url": "https://github.com/ocaml/opam-repository/archive/d67e70b40203a6a1c77ccb2edbe136c1509a73a3.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
-    "resto": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/resto",
-        "rev": "099145d1997ed8b38c98d9b6197c734d5afa9ea1",
-        "type": "git"
-    },
-    "secp256k1-internal": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/ocaml-secp256k1-internal",
-        "rev": "c54b3e4ac9015ea503132223a5aeb6ac0d752e1b",
-        "type": "git"
-    },
-    "terminal_size": {
-        "branch": "master",
-        "description": "Get the size of the attached terminal in OCaml",
-        "homepage": null,
-        "owner": "cryptosense",
-        "repo": "terminal_size",
-        "rev": "07464b9ead32fa3201fea36a8d21252d20151caa",
-        "sha256": "1yjr2aamy20iw8nw13nzj6h8y5g8aby80kshl53hdnd316vddp0f",
-        "type": "tarball",
-        "url": "https://github.com/cryptosense/terminal_size/archive/07464b9ead32fa3201fea36a8d21252d20151caa.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "tezos": {
-        "ref": "master",
-        "repo": "https://gitlab.com/tezos/tezos",
-        "rev": "be706b7060cc9805d66fce1a032a586d09ee8718",
-        "type": "git"
-    },
     "tezos-opam-repository": {
         "ref": "master",
         "repo": "https://gitlab.com/ligolang/tezos-opam-repository",
         "rev": "dfc46bd895b070bd89028a7ad98741d05ec684df",
         "type": "git"
     },
-    "uecc": {
-        "ref": "master",
-        "repo": "https://gitlab.com/nomadic-labs/ocaml-uecc",
-        "rev": "44e0c343b02702eec7e8011244a7bf61e21a8bf3",
-        "type": "git"
-    },
     "xmldiff": {
         "branch": "master",
         "description": "Diffs on XML trees",