diff --git a/packaging/dev-shell.nix b/packaging/dev-shell.nix
index 7b2638f4e214..72d517d876a8 100644
--- a/packaging/dev-shell.nix
+++ b/packaging/dev-shell.nix
@@ -131,7 +131,7 @@ pkgs.nixComponents2.nix-util.overrideAttrs (
     ignoreCrossFile = flags: builtins.filter (flag: !(lib.strings.hasInfix "cross-file" flag)) flags;
 
     availableComponents = lib.filterAttrs (
-      k: v: lib.meta.availableOn pkgs.hostPlatform v
+      k: v: lib.meta.availableOn pkgs.stdenv.hostPlatform v
     ) allComponents;
 
     activeComponents = buildInputsClosureCond isInternal (
@@ -323,7 +323,7 @@ pkgs.nixComponents2.nix-util.overrideAttrs (
             pkgs.buildPackages.shellcheck
             pkgs.buildPackages.include-what-you-use
           ]
-          ++ lib.optional pkgs.hostPlatform.isUnix pkgs.buildPackages.gdb
+          ++ lib.optional stdenv.hostPlatform.isUnix pkgs.buildPackages.gdb
           ++ lib.optional (stdenv.cc.isClang && stdenv.hostPlatform == stdenv.buildPlatform) (
             lib.hiPrio pkgs.buildPackages.clang-tools
           )
@@ -341,7 +341,7 @@ pkgs.nixComponents2.nix-util.overrideAttrs (
 
     buildInputs =
       # TODO change Nixpkgs to mark gbenchmark as building on Windows
-      lib.optional pkgs.hostPlatform.isUnix pkgs.gbenchmark
+      lib.optional stdenv.hostPlatform.isUnix pkgs.gbenchmark
       ++ dedupByString (v: "${v}") (
         lib.filter (x: !isInternal x) (lib.lists.concatMap (c: c.buildInputs) activeComponents)
       )
diff --git a/src/libstore/meson.build b/src/libstore/meson.build
index 2dc70a0b0c54..a01aa903ae2b 100644
--- a/src/libstore/meson.build
+++ b/src/libstore/meson.build
@@ -158,14 +158,15 @@ sqlite = dependency('sqlite3', 'sqlite', version : '>=3.6.19')
 deps_private += sqlite
 
 s3_aws_auth = get_option('s3-aws-auth')
-aws_crt_cpp = cxx.find_library('aws-crt-cpp', required : s3_aws_auth)
+aws_crt_cpp = dependency(
+  'aws-crt-cpp',
+  required : s3_aws_auth,
+  method : 'cmake',
+  modules : [ 'AWS::aws-crt-cpp' ],
+)
 
 if s3_aws_auth.enabled()
   deps_other += aws_crt_cpp
-  aws_c_common = cxx.find_library('aws-c-common', required : true)
-  deps_other += aws_c_common
-  aws_c_auth = cxx.find_library('aws-c-auth', required : true)
-  deps_other += aws_c_auth
 endif
 
 configdata_pub.set('NIX_WITH_AWS_AUTH', s3_aws_auth.enabled().to_int())
diff --git a/src/libstore/package.nix b/src/libstore/package.nix
index 968c4e3eb91d..1f7b56f2238e 100644
--- a/src/libstore/package.nix
+++ b/src/libstore/package.nix
@@ -14,6 +14,7 @@
   libseccomp,
   nlohmann_json,
   sqlite,
+  cmake, # for resolving aws-crt-cpp dep
 
   busybox-sandbox-shell ? null,
 
@@ -25,7 +26,7 @@
 
   withAWS ?
     # Default is this way because there have been issues building this dependency
-    lib.meta.availableOn stdenv.hostPlatform aws-c-common,
+    (lib.meta.availableOn stdenv.hostPlatform aws-c-common),
 }:
 
 let
@@ -57,7 +58,8 @@ mkMesonLibrary (finalAttrs: {
     (fileset.fileFilter (file: file.hasExt "sql") ./.)
   ];
 
-  nativeBuildInputs = lib.optional embeddedSandboxShell unixtools.hexdump;
+  nativeBuildInputs =
+    lib.optional withAWS cmake ++ lib.optional embeddedSandboxShell unixtools.hexdump;
 
   buildInputs = [
     boost
diff --git a/tests/nixos/default.nix b/tests/nixos/default.nix
index fd7ea61e30f7..c30e872bc1d0 100644
--- a/tests/nixos/default.nix
+++ b/tests/nixos/default.nix
@@ -75,21 +75,6 @@ let
       ];
     };
 
-  otherNixes.nix_2_3.setNixPackage =
-    { lib, pkgs, ... }:
-    {
-      imports = [ checkOverrideNixVersion ];
-      nix.package = lib.mkForce (
-        pkgs.nixVersions.nix_2_3.overrideAttrs (o: {
-          meta = o.meta // {
-            # This version shouldn't be used by end-users, but we run tests against
-            # it to ensure we don't break protocol compatibility.
-            knownVulnerabilities = [ ];
-          };
-        })
-      );
-    };
-
   otherNixes.nix_2_13.setNixPackage =
     { lib, pkgs, ... }:
     {
@@ -106,6 +91,14 @@ let
       );
     };
 
+  otherNixes.nix_2_18.setNixPackage =
+    { lib, pkgs, ... }:
+    {
+      imports = [ checkOverrideNixVersion ];
+      nix.package = lib.mkForce (
+        nixpkgs-23-11.legacyPackages.${pkgs.stdenv.hostPlatform.system}.nixVersions.nix_2_18
+      );
+    };
 in
 
 {
diff --git a/tests/nixos/fsync.nix b/tests/nixos/fsync.nix
index e215e5b3c25c..2af9773336d8 100644
--- a/tests/nixos/fsync.nix
+++ b/tests/nixos/fsync.nix
@@ -40,7 +40,7 @@ in
       for fs in ("ext4", "btrfs", "xfs"):
         machine.succeed("mkfs.{} {} /dev/vdb".format(fs, "-F" if fs == "ext4" else "-f"))
         machine.succeed("mkdir -p /mnt")
-        machine.succeed("mount /dev/vdb /mnt")
+        machine.succeed("mount -t {} /dev/vdb /mnt".format(fs))
         machine.succeed("sync")
         machine.succeed("nix copy --offline ${pkg1} --to /mnt")
         machine.crash()
@@ -48,7 +48,7 @@ in
         machine.start()
         machine.wait_for_unit("multi-user.target")
         machine.succeed("mkdir -p /mnt")
-        machine.succeed("mount /dev/vdb /mnt")
+        machine.succeed("mount -t {} /dev/vdb /mnt".format(fs))
         machine.succeed("nix path-info --offline --store /mnt ${pkg1}")
         machine.succeed("nix store verify --all --store /mnt --no-trust")