diff --git a/release.nix b/release.nix
index f5212047488ccaf4e8e832781145888e702839f8..a47ca862f3bb99554c5ff0f22ffe41e3ef48a5d8 100644
--- a/release.nix
+++ b/release.nix
@@ -1,5 +1,5 @@
 { nix ? builtins.fetchGit ./.
-, nixpkgs ? builtins.fetchGit { url = https://github.com/NixOS/nixpkgs-channels.git; ref = "nixos-19.03"; }
+, nixpkgs ? builtins.fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/nixos-19.03.tar.gz
 , officialRelease ? false
 , systems ? [ "x86_64-linux" "i686-linux" "x86_64-darwin" "aarch64-linux" ]
 }:
diff --git a/shell.nix b/shell.nix
index 73e75fb29c4e8ed019135316aa8aed1adf02a6e5..8167f87a2929ea4de20930470d32d023a8fd1e5f 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,6 +1,6 @@
 { useClang ? false }:
 
-with import (builtins.fetchGit { url = https://github.com/NixOS/nixpkgs-channels.git; ref = "nixos-19.03"; }) {};
+with import (builtins.fetchTarball https://github.com/NixOS/nixpkgs-channels/archive/nixos-19.03.tar.gz) {};
 
 with import ./release-common.nix { inherit pkgs; };