diff --git a/.woodpecker/debug.yaml b/.woodpecker/debug.yaml
index 4c729672..4dc7d3c9 100644
--- a/.woodpecker/debug.yaml
+++ b/.woodpecker/debug.yaml
@@ -12,32 +12,32 @@ when:
 
 steps:
   - name: check formatting
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
-      - nix-shell --attr devShell --run "cargo fmt -- --check"
+      - nix-build -j4 --attr flakePackages.fmt
 
   - name: build
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-build -j4 --attr flakePackages.dev
 
   - name: unit + func tests (lmdb)
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-build -j4 --attr flakePackages.tests-lmdb
 
   - name: unit + func tests (sqlite)
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-build -j4 --attr flakePackages.tests-sqlite
 
   - name: unit + func tests (fjall)
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-build -j4 --attr flakePackages.tests-fjall
 
   - name: integration tests
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-build -j4 --attr flakePackages.dev
       - nix-shell --attr ci --run ./script/test-smoke.sh || (cat /tmp/garage.log; false)
diff --git a/.woodpecker/publish.yaml b/.woodpecker/publish.yaml
index 24a84463..8f3b482f 100644
--- a/.woodpecker/publish.yaml
+++ b/.woodpecker/publish.yaml
@@ -11,7 +11,7 @@ depends_on:
 
 steps:
   - name: refresh-index
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     environment:
       AWS_ACCESS_KEY_ID:
         from_secret: garagehq_aws_access_key_id
@@ -22,7 +22,7 @@ steps:
       - nix-shell --attr ci --run "refresh_index"
 
   - name: multiarch-docker
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     environment:
       DOCKER_AUTH:
         from_secret: docker_auth
diff --git a/.woodpecker/release.yaml b/.woodpecker/release.yaml
index bf2bd8ba..a94a9ccf 100644
--- a/.woodpecker/release.yaml
+++ b/.woodpecker/release.yaml
@@ -19,17 +19,17 @@ matrix:
 
 steps:
   - name: build
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-build --attr releasePackages.${ARCH} --argstr git_version ${CI_COMMIT_TAG:-$CI_COMMIT_SHA}
 
   - name: check is static binary
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-shell --attr ci --run "./script/not-dynamic.sh result/bin/garage"
 
   - name: integration tests
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-shell --attr ci --run ./script/test-smoke.sh || (cat /tmp/garage.log; false)
     when:
@@ -39,7 +39,7 @@ steps:
           ARCH: i386
 
   - name: upgrade tests
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     commands:
       - nix-shell --attr ci --run "./script/test-upgrade.sh v0.8.4 x86_64-unknown-linux-musl" || (cat /tmp/garage.log; false)
     when:
@@ -47,7 +47,7 @@ steps:
           ARCH: amd64
 
   - name: push static binary
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     environment:
       TARGET: "${TARGET}"
       AWS_ACCESS_KEY_ID:
@@ -58,7 +58,7 @@ steps:
       - nix-shell --attr ci --run "to_s3"
 
   - name: docker build and publish
-    image: nixpkgs/nix:nixos-22.05
+    image: nixpkgs/nix:nixos-24.05
     environment:
       DOCKER_PLATFORM: "linux/${ARCH}"
       CONTAINER_NAME: "dxflrs/${ARCH}_garage"
diff --git a/flake.lock b/flake.lock
index 2cfbfda4..211b70e0 100644
--- a/flake.lock
+++ b/flake.lock
@@ -50,17 +50,17 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1736692550,
-        "narHash": "sha256-7tk8xH+g0sJkKLTJFOxphJxxOjMDFMWv24nXslaU2ro=",
+        "lastModified": 1763977559,
+        "narHash": "sha256-g4MKqsIRy5yJwEsI+fYODqLUnAqIY4kZai0nldAP6EM=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "7c4869c47090dd7f9f1bdfb49a22aea026996815",
+        "rev": "cfe2c7d5b5d3032862254e68c37a6576b633d632",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "7c4869c47090dd7f9f1bdfb49a22aea026996815",
+        "rev": "cfe2c7d5b5d3032862254e68c37a6576b633d632",
         "type": "github"
       }
     },
@@ -80,17 +80,17 @@
         ]
       },
       "locked": {
-        "lastModified": 1738549608,
-        "narHash": "sha256-GdyT9QEUSx5k/n8kILuNy83vxxdyUfJ8jL5mMpQZWfw=",
+        "lastModified": 1763952169,
+        "narHash": "sha256-+PeDBD8P+NKauH+w7eO/QWCIp8Cx4mCfWnh9sJmy9CM=",
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "35c6f8c4352f995ecd53896200769f80a3e8f22d",
+        "rev": "ab726555a9a72e6dc80649809147823a813fa95b",
         "type": "github"
       },
       "original": {
         "owner": "oxalica",
         "repo": "rust-overlay",
-        "rev": "35c6f8c4352f995ecd53896200769f80a3e8f22d",
+        "rev": "ab726555a9a72e6dc80649809147823a813fa95b",
         "type": "github"
       }
     },
diff --git a/flake.nix b/flake.nix
index 2fb8c48e..01a077c4 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,13 +2,13 @@
   description =
     "Garage, an S3-compatible distributed object store for self-hosted deployments";
 
-  # Nixpkgs 24.11 as of 2025-01-12
+  # Nixpkgs 25.05 as of 2025-11-24
   inputs.nixpkgs.url =
-    "github:NixOS/nixpkgs/7c4869c47090dd7f9f1bdfb49a22aea026996815";
+    "github:NixOS/nixpkgs/cfe2c7d5b5d3032862254e68c37a6576b633d632";
 
-  # Rust overlay as of 2025-02-03
+  # Rust overlay as of 2025-11-24
   inputs.rust-overlay.url =
-  "github:oxalica/rust-overlay/35c6f8c4352f995ecd53896200769f80a3e8f22d";
+  "github:oxalica/rust-overlay/ab726555a9a72e6dc80649809147823a813fa95b";
   inputs.rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
 
   inputs.crane.url = "github:ipetkov/crane";
@@ -30,6 +30,10 @@
           inherit system nixpkgs crane rust-overlay extraTestEnv;
           release = false;
         }).garage-test;
+        lints = (compile {
+          inherit system nixpkgs crane rust-overlay;
+          release = false;
+        });
       in
       {
         packages = {
@@ -56,6 +60,10 @@
           tests-fjall = testWith {
             GARAGE_TEST_INTEGRATION_DB_ENGINE = "fjall";
           };
+
+          # lints (fmt, clippy)
+          fmt = lints.garage-cargo-fmt;
+          clippy = lints.garage-cargo-clippy;
         };
 
         # ---- developpment shell, for making native builds only ----
diff --git a/nix/compile.nix b/nix/compile.nix
index 7e9f79ab..c6df9dbd 100644
--- a/nix/compile.nix
+++ b/nix/compile.nix
@@ -48,7 +48,7 @@ let
 
   inherit (pkgs) lib stdenv;
 
-  toolchainFn = (p: p.rust-bin.stable."1.82.0".default.override {
+  toolchainFn = (p: p.rust-bin.stable."1.91.0".default.override {
     targets = lib.optionals (target != null) [ rustTarget ];
     extensions = [
       "rust-src"
@@ -190,4 +190,15 @@ in rec {
       pkgs.cacert
     ];
   } // extraTestEnv);
+
+  # ---- source code linting ----
+
+  garage-cargo-fmt = craneLib.cargoFmt (commonArgs // {
+    cargoExtraArgs = "";
+  });
+
+  garage-cargo-clippy = craneLib.cargoClippy (commonArgs // {
+    cargoArtifacts = garage-deps;
+    cargoClippyExtraArgs = "--all-targets -- -D warnings";
+  });
 }
diff --git a/script/dev-env-aws.sh b/script/dev-env-aws.sh
index 808f9cf1..41f1fdde 100644
--- a/script/dev-env-aws.sh
+++ b/script/dev-env-aws.sh
@@ -1,6 +1,7 @@
 export AWS_ACCESS_KEY_ID=`cat /tmp/garage.s3 |cut -d' ' -f1`
 export AWS_SECRET_ACCESS_KEY=`cat /tmp/garage.s3 |cut -d' ' -f2`
 export AWS_DEFAULT_REGION='garage'
+export AWS_REQUEST_CHECKSUM_CALCULATION='when_required'
 # FUTUREWORK: set AWS_ENDPOINT_URL instead, once nixpkgs bumps awscli to >=2.13.0.
 function aws { command aws --endpoint-url http://127.0.0.1:3911 $@ ; }
 
diff --git a/shell.nix b/shell.nix
index cfccfe94..c3dedca8 100644
--- a/shell.nix
+++ b/shell.nix
@@ -34,6 +34,8 @@ in
       jq
     ];
     shellHook = ''
+      export AWS_REQUEST_CHECKSUM_CALCULATION='when_required'
+
       function to_s3 {
         aws \
             --endpoint-url https://garage.deuxfleurs.fr \