diff --git a/apps/browser-demos/lib/init/index.ts b/apps/browser-demos/lib/init/index.ts
index 166579e3f0..45d42b07ef 100644
--- a/apps/browser-demos/lib/init/index.ts
+++ b/apps/browser-demos/lib/init/index.ts
@@ -23,6 +23,3 @@ export { COREUTILS_NAMES } from "./shell-binaries";
 
 // Service worker bridge
 export { initServiceWorkerBridge } from "./service-worker-bridge";
-
-// MariaDB directory setup
-export { populateMariadbDirs } from "./mariadb-config";
diff --git a/apps/browser-demos/lib/init/mariadb-config.ts b/apps/browser-demos/lib/init/mariadb-config.ts
deleted file mode 100644
index e19b8ab109..0000000000
--- a/apps/browser-demos/lib/init/mariadb-config.ts
+++ /dev/null
@@ -1,24 +0,0 @@
-/**
- * MariaDB directory setup for the kandelo browser environment.
- *
- * Creates the data directory structure MariaDB needs for bootstrap and
- * server operation.
- */
-import type { MemoryFileSystem } from "../../../../host/src/vfs/memory-fs";
-import { ensureDir } from "./vfs-utils";
-
-/**
- * Create the MariaDB data directory structure.
- *
- * Directories:
- *   /data         — main data directory (--datadir)
- *   /data/mysql   — system tables
- *   /data/tmp     — temporary files (--tmpdir)
- *   /data/test    — default test database
- */
-export function populateMariadbDirs(fs: MemoryFileSystem): void {
-  ensureDir(fs, "/data");
-  ensureDir(fs, "/data/mysql");
-  ensureDir(fs, "/data/tmp");
-  ensureDir(fs, "/data/test");
-}
diff --git a/images/vfs/scripts/build-lamp-vfs-image.ts b/images/vfs/scripts/build-lamp-vfs-image.ts
index 57881a9e41..f543d97aa9 100644
--- a/images/vfs/scripts/build-lamp-vfs-image.ts
+++ b/images/vfs/scripts/build-lamp-vfs-image.ts
@@ -49,6 +49,7 @@ import {
 import { MYSQL_BENCHMARK_PHP } from "../../../apps/browser-demos/lib/init/mysql-benchmark";
 import { loadShellBaseFileSystem } from "./shell-vfs-build";
 import { preinstallWordPressMariaDb } from "./wordpress-preinstall";
+import { prepareMariadbWritableDirectories } from "./mariadb-image-helpers";
 
 const REPO_ROOT = findRepoRoot();
 const BROWSER_DIR = join(REPO_ROOT, "apps", "browser-demos");
@@ -77,8 +78,6 @@ const OPCACHE_SO_PATH = resolveBinary("programs/php/opcache.so");
 const MSMTPD_PATH = resolveBinary("programs/msmtpd.wasm");
 const OUT_FILE = join(BROWSER_DIR, "public", "lamp.vfs.zst");
 const PHP_FPM_WORKERS = 6;
-const MYSQL_UID = 101;
-const MYSQL_GID = 101;
 const MARIADB_SOCKET_PATH = "/tmp/mysql.sock";
 const LAMP_IMAGE_MAX_BYTES = 768 * 1024 * 1024;
 const MARIADB_ARIA_LOG_FILE_SIZE = 16 * 1024 * 1024;
@@ -87,19 +86,6 @@ const MARIADB_INNODB_LOG_FILE_SIZE = 16 * 1024 * 1024;
 const MARIADB_INNODB_LOG_BUFFER_SIZE = 1024 * 1024;
 const MARIADB_INNODB_BUFFER_POOL_SIZE = 8 * 1024 * 1024;
 
-// LAMP-specific data dirs that mariadbd writes to at runtime. The image
-// starts from the full shell demo VFS, so the bootstrap script gets the same
-// /bin/sh and utility layout users see in the interactive terminal.
-function populateMariadbDataDirs(fs: MemoryFileSystem): void {
-  for (const dir of ["/data", "/data/mysql", "/data/tmp", "/data/test"]) {
-    ensureDirRecursive(fs, dir);
-    fs.chown(dir, MYSQL_UID, MYSQL_GID);
-    fs.chmod(dir, 0o775);
-  }
-  ensureDirRecursive(fs, "/tmp");
-  fs.chmod("/tmp", 0o1777);
-}
-
 function populateMariadb(fs: MemoryFileSystem): void {
   ensureDirRecursive(fs, "/usr/sbin");
   writeVfsBinary(fs, "/usr/sbin/mariadbd", new Uint8Array(readFileSync(MARIADB_PATH)));
@@ -430,7 +416,7 @@ async function main() {
 
   console.log("Loading shell base image...");
   const fs = loadShellBaseFileSystem(LAMP_IMAGE_MAX_BYTES);
-  populateMariadbDataDirs(fs);
+  prepareMariadbWritableDirectories(fs);
 
   console.log("Writing nginx + php-fpm + msmtpd binaries...");
   ensureDirRecursive(fs, "/usr/sbin");
diff --git a/packages/registry/lamp/build.toml b/packages/registry/lamp/build.toml
index 3153c80868..5e14698f88 100644
--- a/packages/registry/lamp/build.toml
+++ b/packages/registry/lamp/build.toml
@@ -11,6 +11,7 @@ inputs = [
   "images/rootfs/etc/services",
   "images/vfs/scripts/kandelo-demo-config.ts",
   "images/vfs/scripts/kandelo-demo-guides.ts",
+  "images/vfs/scripts/mariadb-image-helpers.ts",
   "images/vfs/scripts/opcache-prewarm.ts",
   "images/vfs/scripts/shell-vfs-build.ts",
   "images/vfs/scripts/smtp-capture-helpers.ts",