diff --git a/pkgs/applications/science/logic/abc/default.nix b/pkgs/applications/science/logic/abc/default.nix
index c832d12627a..8551a3ee4ca 100644
--- a/pkgs/applications/science/logic/abc/default.nix
+++ b/pkgs/applications/science/logic/abc/default.nix
@@ -1,16 +1,20 @@
 { fetchFromGitHub, stdenv, readline, cmake }:
 
-stdenv.mkDerivation {
+let
+  rev = "71f2b40320127561175ad60f6f2428f3438e5243";
+in stdenv.mkDerivation {
   pname = "abc-verifier";
-  version = "2018-07-08";
+  version = "2020-01-11";
 
   src = fetchFromGitHub {
+    inherit rev;
     owner = "berkeley-abc";
     repo = "abc";
-    rev    = "24407e13db4b8ca16c3996049b2d33ec3722de39";
-    sha256 = "1rckji7nk81n6v1yajz7daqwipxacv7zlafknvmbiwji30j47sq5";
+    sha256 = "15sn146ajxql7l1h8rsag5lhn4spwvgjhwzqawfr78snzadw8by3";
   };
 
+  passthru.rev = rev;
+
   nativeBuildInputs = [ cmake ];
   buildInputs = [ readline ];
 
diff --git a/pkgs/development/compilers/yosys/default.nix b/pkgs/development/compilers/yosys/default.nix
index 8948af17145..7027c5a0523 100644
--- a/pkgs/development/compilers/yosys/default.nix
+++ b/pkgs/development/compilers/yosys/default.nix
@@ -1,75 +1,65 @@
-{ stdenv, fetchFromGitHub
-, pkgconfig, bison, flex
-, tcl, readline, libffi, python3
-, protobuf, zlib
+{ stdenv
+, abc-verifier
+, bison
+, fetchFromGitHub
+, flex
+, libffi
+, pkgconfig
+, protobuf
+, python3
+, readline
+, tcl
 , verilog
+, zlib
 }:
 
-with builtins;
-
 stdenv.mkDerivation rec {
   pname = "yosys";
-  version = "2019.10.18";
+  version = "2020.02.01";
 
-  srcs = [
-    (fetchFromGitHub {
-      owner  = "yosyshq";
-      repo   = "yosys";
-      rev    = "3c41599ee1f62e4d77ba630fa1a245ef3fe236fa";
-      sha256 = "0jg2g8v08ax1q6qlvn8c1h147m03adzrgf21043xwbh4c7s5k137";
-      name   = "yosys";
-    })
-
-    # NOTE: the version of abc used here is synchronized with
-    # the one in the yosys Makefile of the version above;
-    # keep them the same for quality purposes.
-    (fetchFromGitHub {
-      owner  = "berkeley-abc";
-      repo   = "abc";
-      rev    = "623b5e82513d076a19f864c01930ad1838498894";
-      sha256 = "1mrfqwsivflqdzc3531r6mzp33dfyl6dnqjdwfcq137arqh36m67";
-      name   = "yosys-abc";
-    })
-  ];
-  sourceRoot = "yosys";
+  src = fetchFromGitHub {
+    owner  = "yosyshq";
+    repo   = "yosys";
+    rev    = "a1c840ca5d6e8b580e21ae48550570aa9665741a";
+    sha256 = "1vna04dh6l68nifssgs3hxqwn4k529krmm4crj94a8wwhwra52mh";
+    name   = "yosys";
+  };
 
   enableParallelBuilding = true;
   nativeBuildInputs = [ pkgconfig ];
   buildInputs = [ tcl readline libffi python3 bison flex protobuf zlib ];
 
-  makeFlags = [ "ENABLE_PROTOBUF=1" ];
+  makeFlags = [ "ENABLE_PROTOBUF=1" "PREFIX=${placeholder "out"}"];
 
   patchPhase = ''
-    substituteInPlace ../yosys-abc/Makefile \
-      --replace 'CC   := gcc' "" \
-      --replace 'CXX  := g++' ""
     substituteInPlace ./Makefile \
       --replace 'CXX = clang' "" \
       --replace 'LD = clang++' 'LD = $(CXX)' \
       --replace 'CXX = gcc' "" \
       --replace 'LD = gcc' 'LD = $(CXX)' \
       --replace 'ABCMKARGS = CC="$(CXX)" CXX="$(CXX)"' 'ABCMKARGS =' \
-      --replace 'echo UNKNOWN' 'echo ${substring 0 10 (elemAt srcs 0).rev}'
+      --replace 'echo UNKNOWN' 'echo ${builtins.substring 0 10 src.rev}'
     patchShebangs tests
   '';
 
-  preBuild = ''
-    chmod -R u+w ../yosys-abc
-    ln -s ../yosys-abc abc
+  preBuild = let
+    shortAbcRev = builtins.substring 0 7 abc-verifier.rev;
+  in ''
+    chmod -R u+w .
     make config-${if stdenv.cc.isClang or false then "clang" else "gcc"}
-    echo 'ABCREV := default' >> Makefile.conf
-    makeFlags="PREFIX=$out $makeFlags"
+    echo 'ABCEXTERNAL = ${abc-verifier}/bin/abc' >> Makefile.conf
 
     # we have to do this ourselves for some reason...
     (cd misc && ${protobuf}/bin/protoc --cpp_out ../backends/protobuf/ ./yosys.proto)
+
+    if ! grep -q "ABCREV = ${shortAbcRev}" Makefile;then
+      echo "yosys isn't compatible with the provided abc (${shortAbcRev}), failing."
+      exit 1
+    fi
   '';
 
   doCheck = true;
   checkInputs = [ verilog ];
-  # checkPhase defaults to VERBOSE=y, which gets passed down to abc,
-  # which then does $(VERBOSE)gcc, which then complains about not
-  # being able to find ygcc. Life is pain.
-  checkFlags = [ " " ];
 
   meta = {
     description = "Framework for RTL synthesis tools";