diff --git a/flake.lock b/flake.lock
index 96fa2fa..e8df58a 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,28 +1,12 @@
 {
   "nodes": {
-    "mozilla-overlay": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1704373101,
-        "narHash": "sha256-+gi59LRWRQmwROrmE1E2b3mtocwueCQqZ60CwLG+gbg=",
-        "owner": "mozilla",
-        "repo": "nixpkgs-mozilla",
-        "rev": "9b11a87c0cc54e308fa83aac5b4ee1816d5418a2",
-        "type": "github"
-      },
-      "original": {
-        "owner": "mozilla",
-        "repo": "nixpkgs-mozilla",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1720386169,
-        "narHash": "sha256-NGKVY4PjzwAa4upkGtAMz1npHGoRzWotlSnVlqI40mo=",
+        "lastModified": 1721548954,
+        "narHash": "sha256-7cCC8+Tdq1+3OPyc3+gVo9dzUNkNIQfwSDJ2HSi2u3o=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "194846768975b7ad2c4988bdb82572c00222c0d7",
+        "rev": "63d37ccd2d178d54e7fb691d7ec76000740ea24a",
         "type": "github"
       },
       "original": {
@@ -34,8 +18,28 @@
     },
     "root": {
       "inputs": {
-        "mozilla-overlay": "mozilla-overlay",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1721701191,
+        "narHash": "sha256-nM4szL90VeZHZEC5rFfaiiPNTVOmsihdtk2QSP1l37I=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "4674ff2c2e5423a0cebe16e61aa874c359306af4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index d5b7144..fd98b03 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,37 +2,47 @@
   description = "Bare-metal Rust on Zynq-7000";
 
   inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-24.05;
-  inputs.mozilla-overlay = { url = github:mozilla/nixpkgs-mozilla; flake = false; };
+  #inputs.mozilla-overlay = { url = github:mozilla/nixpkgs-mozilla; flake = false; };
+  inputs.rust-overlay = {
+    url = "github:oxalica/rust-overlay";
+    inputs.nixpkgs.follows = "nixpkgs";
+  };
 
-  outputs = { self, nixpkgs, mozilla-overlay }:
+  outputs = { self, nixpkgs, rust-overlay }:
     let
-      pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import mozilla-overlay) crosspkgs-overlay ]; };
+      pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ (import rust-overlay) crosspkgs-overlay ]; };
       
-      rustManifest = pkgs.fetchurl {
-        url = "https://static.rust-lang.org/dist/2021-01-29/channel-rust-nightly.toml";
-        sha256 = "sha256-EZKgw89AH4vxaJpUHmIMzMW/80wAFQlfcxRoBD9nz0c=";
+      # rustManifest = pkgs.fetchurl {
+      #   url = "https://static.rust-lang.org/dist/2021-01-29/channel-rust-nightly.toml";
+      #   sha256 = "sha256-EZKgw89AH4vxaJpUHmIMzMW/80wAFQlfcxRoBD9nz0c=";
+      # };
+      # rustTargets = [];
+      # rustChannelOfTargets = _channel: _date: targets:
+      #   (pkgs.lib.rustLib.fromManifestFile rustManifest {
+      #     inherit (pkgs) stdenv lib fetchurl patchelf;
+      #     }).rust.override {
+      #     inherit targets;
+      #     extensions = ["rust-src"];
+      #   };
+      # rust = rustChannelOfTargets "nightly" null rustTargets;
+
+      # rustc version needs to match LLVM version, else ABI bugs
+      # https://doc.rust-lang.org/rustc/linker-plugin-lto.html#toolchain-compatibility
+      rust = pkgs.rust-bin.nightly."2023-04-20".default.override {
+        extensions = [ "rust-src" ];
       };
-      rustTargets = [];
-      rustChannelOfTargets = _channel: _date: targets:
-        (pkgs.lib.rustLib.fromManifestFile rustManifest {
-          inherit (pkgs) stdenv lib fetchurl patchelf;
-          }).rust.override {
-          inherit targets;
-          extensions = ["rust-src"];
-        };
-      rust = rustChannelOfTargets "nightly" null rustTargets;
       rustPlatform = pkgs.recurseIntoAttrs (pkgs.makeRustPlatform {
         rustc = rust;
         cargo = rust;
       });
       
-      # https://doc.rust-lang.org/rustc/linker-plugin-lto.html#toolchain-compatibility
-      llvmPackages_11 = pkgs.recurseIntoAttrs (pkgs.callPackage (import ./llvm/11) ({
-        inherit (pkgs.stdenvAdapters) overrideCC;
-        buildLlvmTools = null;
-        targetLlvmLibraries = null;
-        targetLlvm = null;
-      }));
+      ## https://doc.rust-lang.org/rustc/linker-plugin-lto.html#toolchain-compatibility
+      #llvmPackages_11 = pkgs.recurseIntoAttrs (pkgs.callPackage (import ./llvm/11) ({
+      #  inherit (pkgs.stdenvAdapters) overrideCC;
+      #  buildLlvmTools = null;
+      #  targetLlvmLibraries = null;
+      #  targetLlvm = null;
+      #}));
 
       crosspkgs-overlay = (self: super: {
         pkgsCross = super.pkgsCross // {
@@ -104,9 +114,13 @@
         dontFixup = true;
       };
 
-      cargo-xbuild = pkgs.cargo-xbuild.overrideAttrs(oa: {
-        postPatch = "substituteInPlace src/sysroot.rs --replace 2021 2018";
-      });
+      cargo-xbuild = pkgs.cargo-xbuild;
+      #cargo-xbuild = pkgs.cargo-xbuild.overrideAttrs(oa: {
+      #  postPatch = "substituteInPlace src/sysroot.rs --replace 2021 2018";
+      #});
+      #cargo-xbuild = pkgs.cargo-xbuild.overrideAttrs(oa: {
+      #  postPatch = "substituteInPlace src/sysroot.rs --replace 2023 2018";
+      #});
 
       build-crate = name: crate: features: rustPlatform.buildRustPackage rec {
         name = "${crate}";
@@ -116,7 +130,7 @@
         ) ./.;
         cargoLock = { lockFile = ./Cargo.lock; };
 
-        nativeBuildInputs = [ cargo-xbuild llvmPackages_11.clang-unwrapped ];
+        nativeBuildInputs = [ cargo-xbuild pkgs.llvmPackages_16.clang-unwrapped ];
         buildPhase = ''
           export XARGO_RUST_SRC="${rust}/lib/rustlib/src/rust/library"
           export CARGO_HOME=$(mktemp -d cargo-home.XXX)
@@ -161,7 +175,7 @@
 
       hydraJobs = packages.x86_64-linux;
 
-      inherit rust rustPlatform llvmPackages_11;
+      inherit rust rustPlatform;
 
       devShell.x86_64-linux = pkgs.mkShell {
         name = "zynq-rs-dev-shell";
@@ -172,7 +186,7 @@
 
           pkgs.openocd pkgs.gdb
           pkgs.openssh pkgs.rsync
-          llvmPackages_11.clang-unwrapped
+          pkgs.llvmPackages_16.clang-unwrapped
           (pkgs.python3.withPackages(ps: [ ps.pyftdi ]))
         ];
       };