diff --git a/default.nix b/default.nix
index df43e7a..f3f0f0c 100644
--- a/default.nix
+++ b/default.nix
@@ -19,7 +19,7 @@ let
   toolchainOverlay = import ./toolchain-overlay;
   # Overlay of toolchain patches
 
-in { nixpkgs ? import ./nixpkgs.nix }:
+in { nixpkgs ? import ./nixpkgs.nix, nim-overlay ? <nim-overlay> }:
 
 import nixpkgs {
   # Evaluate an overlayed Nixpkgs for a Genode target
@@ -29,5 +29,5 @@ import nixpkgs {
     isGenode = true;
     imports = [ ./platform.nix ];
   };
-  overlays = [ toolchainOverlay pkgOverlay ];
+  overlays = [ toolchainOverlay (import nim-overlay) pkgOverlay ];
 }
diff --git a/nixpkgs.nix b/nixpkgs.nix
index 4acfac1..37558d9 100644
--- a/nixpkgs.nix
+++ b/nixpkgs.nix
@@ -2,5 +2,5 @@
 builtins.fetchGit {
   url = "https://github.com/ehmry/nixpkgs.git";
   ref = "hybrid-19.09";
-  rev = "84f61071bd0290b6295f6aa5798e6af9ffe3abeb";
+  rev = "0ceffd0334cb5139805591ff5e5934e8e440b7c1";
 }
diff --git a/release.nix b/release.nix
index aa84a2c..ee5e940 100644
--- a/release.nix
+++ b/release.nix
@@ -9,10 +9,11 @@ let dhallPinned = import ./dhallPinnedNixpkgs.nix; in
 , dhall-haskell ? <dhall-haskell>
 , dhallNixpkgs ? dhallPinned.nixpkgs
 , dhallNixpkgsStaticLinux ? dhallPinned.nixpkgsStaticLinux
+, nim-overlay ? <nim-overlay>
 }:
 
 let
-  pkgs = import genodepkgs { inherit nixpkgs; };
+  pkgs = import genodepkgs { inherit nixpkgs nim-overlay; };
   dhall-haskell' = import (dhall-haskell + "/release.nix") {
     nixpkgs = dhallNixpkgs;
     nixpkgsStaticLinux = dhallNixpkgsStaticLinux;