diff --git a/kobol/helios4/default.nix b/kobol/helios4/default.nix
index b40c683..532a757 100644
--- a/kobol/helios4/default.nix
+++ b/kobol/helios4/default.nix
@@ -1,17 +1,44 @@
 { pkgs, ... }:
-
+let
+  linux_5_15_helios4 = pkgs.linux_5_15.override {
+    kernelPatches = [
+      # A patch to get both PWM fans working
+      # the patch has been successfully applied to 5.15 and 5.19
+      {
+        patch = pkgs.fetchpatch {
+          url = "https://raw.githubusercontent.com/armbian/build/bd3466eef2106ea13e85e821f5d852ff97465e6c/patch/kernel/archive/mvebu-5.15/92-mvebu-gpio-remove-hardcoded-timer-assignment.patch";
+          sha256 = "sha256-eQqMp0+MZd30zkl8DE89oB7czvyqCkfwF2k0EZ69jr0=";
+        };
+      }
+      # support for Wake-On-Lan
+      {
+        patch = pkgs.fetchpatch {
+          url = "https://raw.githubusercontent.com/armbian/build/bd3466eef2106ea13e85e821f5d852ff97465e6c/patch/kernel/archive/mvebu-5.15/92-mvebu-gpio-add_wake_on_gpio_support.patch";
+          sha256 = "sha256-OrvnVCU55P0U78jdoxGRJvl29i+Rvq8AdEGSCCpxa2I=";
+        };
+      }
+      {
+        patch = pkgs.fetchpatch {
+          url = "https://raw.githubusercontent.com/armbian/build/bd3466eef2106ea13e85e821f5d852ff97465e6c/patch/kernel/archive/mvebu-5.15/94-helios4-dts-add-wake-on-lan-support.patch";
+          sha256 = "sha256-ai4161bTC22023eaVVWsvbk6fQKjkv0P4DQ4DA1Zgow=";
+        };
+      }
+    ];
+    defconfig = "mvebu_v7_defconfig";
+    # Make the kernel build a bit faster by disabling GPU modules, which we don't need anyways
+    structuredExtraConfig = with pkgs.lib.kernel; {
+      DRM = no;
+    };
+  };
+in
 {
-  imports = [
-    ./modules/fancontrol.nix
-  ];
+  imports = [ ./modules/fancontrol.nix ];
 
-  nixpkgs.overlays = [
-    (import ./overlay.nix)
-  ];
+  nixpkgs.overlays = [ (import ./overlay.nix) ];
 
   nixpkgs.hostPlatform = "armv7l-linux";
 
   boot.initrd.availableKernelModules = [ "ahci_mvebu" ];
 
-  boot.kernelPackages = pkgs.linuxPackagesFor pkgs.linux_5_15_helios4;
+  boot.kernelPackages = pkgs.linuxPackagesFor linux_5_15_helios4;
 }
diff --git a/kobol/helios4/overlay.nix b/kobol/helios4/overlay.nix
index 41aa9d9..32262c5 100644
--- a/kobol/helios4/overlay.nix
+++ b/kobol/helios4/overlay.nix
@@ -1,36 +1,4 @@
 final: _prev: {
-  linux_5_15_helios4 = final.linux_5_15.override {
-    kernelPatches = [
-      # A patch to get both PWM fans working
-      # the patch has been successfully applied to 5.15 and 5.19
-      {
-        patch = final.fetchpatch {
-          url = "https://raw.githubusercontent.com/armbian/build/bd3466eef2106ea13e85e821f5d852ff97465e6c/patch/kernel/archive/mvebu-5.15/92-mvebu-gpio-remove-hardcoded-timer-assignment.patch";
-          sha256 = "sha256-eQqMp0+MZd30zkl8DE89oB7czvyqCkfwF2k0EZ69jr0=";
-        };
-      }
-      # support for Wake-On-Lan
-      {
-        patch = final.fetchpatch {
-          url = "https://raw.githubusercontent.com/armbian/build/bd3466eef2106ea13e85e821f5d852ff97465e6c/patch/kernel/archive/mvebu-5.15/92-mvebu-gpio-add_wake_on_gpio_support.patch";
-          sha256 = "sha256-OrvnVCU55P0U78jdoxGRJvl29i+Rvq8AdEGSCCpxa2I=";
-        };
-      }
-      {
-        patch = final.fetchpatch {
-          url = "https://raw.githubusercontent.com/armbian/build/bd3466eef2106ea13e85e821f5d852ff97465e6c/patch/kernel/archive/mvebu-5.15/94-helios4-dts-add-wake-on-lan-support.patch";
-          sha256 = "sha256-ai4161bTC22023eaVVWsvbk6fQKjkv0P4DQ4DA1Zgow=";
-        };
-      }
-
-    ];
-    defconfig = "mvebu_v7_defconfig";
-    # Make the kernel build a bit faster by disabling GPU modules, which we don't need anyways
-    structuredExtraConfig = with final.lib.kernel; {
-      DRM = no;
-    };
-  };
-
   ubootHelios4 = final.buildUBoot rec {
     defconfig = "helios4_defconfig";
     filesToInstall = [ "u-boot-spl.kwb" ];
diff --git a/purism/librem/5r4/audio.nix b/purism/librem/5r4/audio.nix
index e44e2f3..80c1c87 100644
--- a/purism/librem/5r4/audio.nix
+++ b/purism/librem/5r4/audio.nix
@@ -9,7 +9,7 @@
       enable = true;
       # this is required to correctly configure the modem as PA source/sink
       extraConfig = ''
-        .include ${pkgs.librem5-base}/etc/pulse/librem5.pa
+        .include ${config.hardware.librem5.package}/etc/pulse/librem5.pa
       '';
     };
 
diff --git a/purism/librem/5r4/default.nix b/purism/librem/5r4/default.nix
index 83c7fb3..76854a6 100644
--- a/purism/librem/5r4/default.nix
+++ b/purism/librem/5r4/default.nix
@@ -1,8 +1,15 @@
 { config, pkgs, lib, ... }:
-let cfg = config.hardware.librem5;
+let
+  cfg = config.hardware.librem5;
+  linuxPackages_librem5 = pkgs.linuxPackagesFor (pkgs.callPackage ./kernel.nix { });
+  ubootLibrem5 = pkgs.callPackage ./u-boot { };
 in {
   options = {
     hardware.librem5 = {
+      package = lib.mkOption {
+        type = lib.types.package;
+        default = pkgs.callPackage ./librem5-base { };
+      };
       wifiCard = lib.mkOption {
         type = lib.types.enum [ "redpine" "sparklan" "none" ];
         description = lib.mdDoc ''
@@ -42,15 +49,6 @@ in {
       lockdownFix = lib.mkDefault true;
     };
 
-    nixpkgs.overlays = [
-      (import ./kernel)
-      (final: prev: {
-        ubootLibrem5 = final.callPackage ./u-boot { };
-
-        librem5-base = final.callPackage ./librem5-base { };
-      })
-    ];
-
     boot = {
       kernelParams = [ "rootwait" ];
 
@@ -59,12 +57,11 @@ in {
         grub.enable = false;
       };
 
-      kernelPackages = lib.mkDefault pkgs.linuxPackages_librem5;
+      kernelPackages = lib.mkDefault linuxPackages_librem5;
     };
 
-    services.udev.packages = lib.mkIf cfg.installUdevPackages [ pkgs.librem5-base ];
-
-    environment.systemPackages = with pkgs; [ ubootLibrem5 ];
+    services.udev.packages = lib.mkIf cfg.installUdevPackages [ config.hardware.librem5.package ];
 
+    environment.systemPackages = [ ubootLibrem5 ];
   };
 }
diff --git a/purism/librem/5r4/kernel/kernel.nix b/purism/librem/5r4/kernel.nix
similarity index 100%
rename from purism/librem/5r4/kernel/kernel.nix
rename to purism/librem/5r4/kernel.nix
diff --git a/purism/librem/5r4/kernel/default.nix b/purism/librem/5r4/kernel/default.nix
deleted file mode 100644
index 7b1b085..0000000
--- a/purism/librem/5r4/kernel/default.nix
+++ /dev/null
@@ -1,3 +0,0 @@
-final: prev: {
-  linuxPackages_librem5 = final.linuxPackagesFor (final.callPackage ./kernel.nix { });
-}
diff --git a/purism/librem/5r4/lockdown-fix.nix b/purism/librem/5r4/lockdown-fix.nix
index 00e5041..121ded3 100644
--- a/purism/librem/5r4/lockdown-fix.nix
+++ b/purism/librem/5r4/lockdown-fix.nix
@@ -11,7 +11,7 @@ lib.mkIf config.hardware.librem5.lockdownFix {
   systemd.services.librem5-lockdown-support = {
     description = "Set up drivers for the orientation and proximity sensors on Librem 5";
     serviceConfig.Type = "oneshot";
-    serviceConfig.ExecStart = "${pkgs.librem5-base}/bin/lockdown-support.sh";
+    serviceConfig.ExecStart = "${config.hardware.librem5.package}/bin/lockdown-support.sh";
     wantedBy = [ "default.target" ];
     path = [ pkgs.kmod ];
   };