diff --git a/default.nix b/default.nix
index 1535c8082ef84292de6b47575d960b207f4604c8..09a46c57509da9de75073f4a0e755d4c92c7a8cb 100644
--- a/default.nix
+++ b/default.nix
@@ -6,7 +6,7 @@
 
   overlays = pkgs.callPackage ./nix/overlays.nix {};
 
-  packageSet = pkgs.opamPackages.overrideScope' (pkgs.lib.composeManyExtensions [
+  packageSet = pkgs.opamPackages.overrideScope (pkgs.lib.composeManyExtensions [
     # Set the opam-repository which has the package descriptions.
     (final: prev: {
       repository = prev.repository.override {src = sources.opam-repository;};
diff --git a/flake.lock b/flake.lock
index 0183fddfbe45d9eb0e7930e1d595593c62a4c263..628d2b938afd05867fa3ce270144143ef21ed685 100644
--- a/flake.lock
+++ b/flake.lock
@@ -52,27 +52,26 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1717179513,
-        "narHash": "sha256-vboIEwIQojofItm2xGCdZCzW96U85l9nDW3ifMuAIdM=",
+        "lastModified": 1733409684,
+        "narHash": "sha256-Kg8bvWdJ1u/IH8Ro/RGlG5mvAsqnC3VnlsgjIG/FtwQ=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "63dacb46bf939521bdc93981b4cbb7ecb58427a0",
+        "rev": "4bd660accd40798001cb010e0f7f85903bd61c09",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "24.05",
         "repo": "nixpkgs",
         "type": "github"
       }
     },
     "nixpkgs_2": {
       "locked": {
-        "lastModified": 1688587528,
-        "narHash": "sha256-a1WlbVZyFtXVwqU/Ut+tl8aTgexp/GKloQtGA1Hfwjw=",
+        "lastModified": 1733413205,
+        "narHash": "sha256-J/Mr9HW5kT+pfOQoXF6U4a8NdPr/yKqTttkjaut4a64=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "08c696c8d702e98d6693efea6d0be94b54849a16",
+        "rev": "7822cb34f86bcdd0b9f31f2955062216857a6757",
         "type": "github"
       },
       "original": {
@@ -106,11 +105,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1728662094,
-        "narHash": "sha256-tOAquEaPr15wNWbfsxNqV6s6oCfC0yQvC5D5MRKm+ig=",
+        "lastModified": 1733485420,
+        "narHash": "sha256-8tdWH9ojaXR95yvskNO62ugSMpZdsOX/ipU0rPPWsok=",
         "owner": "vapourismo",
         "repo": "opam-nix-integration",
-        "rev": "576bfd60b8fc1cf548ae71b842496a15a797f4fd",
+        "rev": "698b636dc194511a818bdf9ba2f9d5639e268bea",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 10b625aecfc502088b63e1d8fc5b18ffae66c8c2..8618029db0ba9b8782bc476760e5863ae8cd2b53 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,7 +3,7 @@
 # continue to work in the future.
 {
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/24.05";
+    nixpkgs.url = "github:NixOS/nixpkgs";
     flake-utils.url = "github:numtide/flake-utils";
     opam-nix-integration = {
       url = "github:vapourismo/opam-nix-integration";
diff --git a/nix/sources.nix b/nix/sources.nix
index 348f37913acfdbea3e76181a1ad2287d10642927..d32be0abf5d4b773c9a2294063cde0699ff8d8b4 100644
--- a/nix/sources.nix
+++ b/nix/sources.nix
@@ -46,7 +46,7 @@ in
     };
 
     riscv64Pkgs = import pkgs-src {
-      crossSystem.config = "riscv64-unknown-linux-gnu";
+      crossSystem.config = "riscv64-unknown-linux-musl";
     };
 
     opam-repository = pkgs.callPackage ./opam-repo.nix {};
diff --git a/shell.nix b/shell.nix
index 1595743a898c513960285857a74fc7f3f0b6b664..6781fe766155fc78ee1fcdc76673fa084e5b18a6 100644
--- a/shell.nix
+++ b/shell.nix
@@ -13,7 +13,7 @@
       pkgs.wabt
 
       # Cross-compilation for RISC-V
-      sources.riscv64Pkgs.clangStdenv.cc
+      sources.pkgs.pkgsCross.riscv64.pkgsStatic.stdenv.cc
 
       # Formatter/LSP for Cargo manifests (and TOML in general)
       pkgs.taplo
@@ -30,7 +30,7 @@
     src = null;
   });
 
-  devPackageSet = pkgs.opamPackages.overrideScope' (
+  devPackageSet = pkgs.opamPackages.overrideScope (
     pkgs.lib.composeManyExtensions [
       # Set the opam-repository which has the package descriptions.
       (final: prev: {
@@ -127,6 +127,7 @@ in
     # targeting other architectures.
     CC_wasm32_unknown_unknown = "${clangNoArch}/bin/clang";
     CC_riscv64gc_unknown_linux_gnu = "${clangNoArch}/bin/clang";
+    CC_riscv64gc_unknown_linux_musl = "${clangNoArch}/bin/clang";
     CC_riscv64gc_unknown_none_elf = "${clangNoArch}/bin/clang";
     CC_riscv64gc_unknown_hermit = "${clangNoArch}/bin/clang";
   }