chore: include kernel modules in rootfs as sysext

pkgs/kernel/manual-config.nix

@@ -22,6 +22,8 @@
   pahole,
   kmod,
   ubootTools,
+  erofs-utils,
+  cryptsetup,
   fetchpatch,
   rustc,
   rust-bindgen,
@@ -224,6 +226,8 @@ lib.makeOverridable (
             python3Minimal
             kmod
             hexdump
+            erofs-utils
+            cryptsetup
           ]
           ++ optional needsUbootTools ubootTools
           ++ optionals (lib.versionAtLeast version "5.2") [
@@ -496,6 +500,20 @@ lib.makeOverridable (
 
           # Delete empty directories
           find -empty -type d -delete
+
+          pkgName="patos-kernel-modules"
+          mkdir -p $out/tree/usr/lib/extension-release.d
+          cat << EOF > $out/tree/usr/lib/extension-release.d/extension-release.$pkgName
+          ID=patos
+          IMAGE_ID=$pkgName
+          IMAGE_VERSION=${version}
+          VERSION_ID=patos
+          EOF
+          cp -Prp $out/lib/modules $out/tree/usr/lib/modules
+          find $out/tree -type d -exec chmod 0755 {} \;
+          mkfs.erofs --all-root -zlz4hc,12 -C1048576 -Efragments,dedupe,ztailpacking $out/$pkgName.raw $out/tree/
+          veritysetup format --root-hash-file $out/$pkgName.roothash $out/$pkgName.raw $out/$pkgName.verity
+          chmod -R 755 $out/tree && rm -rf $out/tree
         '';
 
         requiredSystemFeatures = [ "big-parallel" ];