diff --git a/pkgs/default.nix b/pkgs/default.nix
index fb3b2e9..b828554 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -13,7 +13,7 @@
   python_ot = pkgs.callPackage ./python_ot {inherit inputs;};
   bazel_ot = pkgs.callPackage ./bazel_ot {};
   llvm_cheriot = pkgs.callPackage ./llvm_cheriot.nix {};
-  ibex-cosim = pkgs.callPackage ./ibex-cosim.nix {};
+  spike_ibex_cosim = pkgs.callPackage ./spike.nix {};
 }
 // pkgs.lib.optionalAttrs (pkgs.system == "x86_64-linux") {
   lowrisc-toolchain-gcc-rv32imcb = pkgs.callPackage ./lowrisc-toolchain-gcc-rv32imcb.nix {};
diff --git a/pkgs/ibex-cosim.nix b/pkgs/ibex-cosim.nix
deleted file mode 100644
index 06ce11f..0000000
--- a/pkgs/ibex-cosim.nix
+++ /dev/null
@@ -1,28 +0,0 @@
-{
-  fetchFromGitHub,
-  stdenv,
-  dtc,
-}:
-stdenv.mkDerivation rec {
-  pname = "ibex-cosim";
-  version = "15fbd56";
-
-  src = fetchFromGitHub {
-    owner = "lowRISC";
-    repo = "riscv-isa-sim";
-    # branch ibex_cosim
-    rev = "15fbd5680e44da699f828c67db15345822a47ef6";
-    hash = "sha256-LK/IXmRHrGxaMRudcUYmeZV5eXU8eH7ruIw7kliumdY=";
-  };
-
-  nativeBuildInputs = [
-    dtc
-  ];
-
-  configureFlags = [
-    "--enable-commitlog"
-    "--enable-misaligned"
-  ];
-
-  enableParallelBuilding = true;
-}
diff --git a/pkgs/spike.nix b/pkgs/spike.nix
new file mode 100644
index 0000000..b8660f2
--- /dev/null
+++ b/pkgs/spike.nix
@@ -0,0 +1,16 @@
+{
+  fetchFromGitHub,
+  spike,
+}:
+# The lowRISC Ibex processor (https://github.com/lowRISC/ibex) uses a fork of
+# spike as an Instruction Set Simulator (ISS) for a cosimulation testbench in
+# its Design Verification (DV) environment.
+spike.overrideAttrs (_: prev: {
+  src = fetchFromGitHub {
+    owner = "lowRISC";
+    repo = "riscv-isa-sim";
+    rev = "ibex-cosim-v0.5";
+    sha256 = "sha256-LK/IXmRHrGxaMRudcUYmeZV5eXU8eH7ruIw7kliumdY=";
+  };
+  configureFlags = (prev.configureFlags or []) ++ ["--enable-commitlog" "--enable-misaligned"];
+})