diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1fd4a94..c1ee99b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,7 +12,18 @@ attribution, not the operator's own name, so on an instance branded "Acme" it of
 branding.
 
 It now reads "Hide platform branding", and the equivalent in the six other translated languages.
-Nothing else changed.
+
+### Fixed — a missing database driver is repaired again on Node 20 and 22
+
+1.9.38 made `better-sqlite3` an optional dependency, so that a host without a compiler installs
+cleanly and falls back to Node's built-in driver. That fallback needs Node 24: on the 20.x and 22.x
+lines the built-in is absent or behind a flag, and there a missing `better-sqlite3` means the server
+cannot start at all.
+
+npm will quietly skip an optional dependency whose install script it declines to run — leaving an
+install that reports success and a server that will not boot. The startup check now treats optional
+dependencies as required on any host that has no built-in driver, and repairs them like any other
+missing package.
 
 ### Upgrading
 
diff --git a/server/lib/preflight-deps.js b/server/lib/preflight-deps.js
index d8cb64b..3854ad6 100644
--- a/server/lib/preflight-deps.js
+++ b/server/lib/preflight-deps.js
@@ -46,6 +46,32 @@ const SERVER_DIR = path.join(__dirname, '..');
 const NODE_MODULES = path.join(SERVER_DIR, 'node_modules');
 const INSTALL_TIMEOUT_MS = 10 * 60 * 1000;   // a cold install on a Pi is genuinely slow
 
+/**
+ * Which dependency names this host actually needs on disk.
+ *
+ * ⚠️ OPTIONAL IS NOT OPTIONAL WHERE THERE IS NOTHING TO FALL BACK TO.
+ *
+ * better-sqlite3 is an optionalDependency so a host with no compiler installs cleanly and lets
+ * db/sqlite-driver.js drop to the built-in node:sqlite. That only works on Node 24 (23.4+); on the
+ * 20.x and 22.x lines the built-in is absent or flagged off, and there a missing better-sqlite3 is
+ * a server that cannot start at all.
+ *
+ * npm will quietly skip an optional dependency whose install script it declines to run. Observed
+ * exactly that: `npm ci` reported success, left no better-sqlite3 on disk, and every test that
+ * spawns the server failed with "server did not boot" — with nothing anywhere saying why.
+ *
+ * Split out from missingDeps so the decision can be tested on either kind of host, rather than only
+ * on whichever Node happens to be running the suite.
+ *
+ * @param {{dependencies?: object, optionalDependencies?: object}} pkg
+ * @param {boolean} builtinDriver whether this runtime has node:sqlite
+ */
+function requiredDeps(pkg, builtinDriver) {
+  const names = Object.keys((pkg && pkg.dependencies) || {});
+  if (!builtinDriver) names.push(...Object.keys((pkg && pkg.optionalDependencies) || {}));
+  return names;
+}
+
 /** Which declared dependencies are not on disk. */
 function missingDeps() {
   let pkg;
@@ -54,7 +80,9 @@ function missingDeps() {
   } catch {
     return [];   // no package.json is not our problem to diagnose
   }
-  const declared = Object.keys(pkg.dependencies || {});
+  let builtinDriver = false;
+  try { require('node:sqlite'); builtinDriver = true; } catch { /* absent on this runtime */ }
+  const declared = requiredDeps(pkg, builtinDriver);
   return declared.filter((name) => {
     // A scoped or nested name is still one directory below node_modules.
     try { return !fs.existsSync(path.join(NODE_MODULES, name, 'package.json')); } catch { return true; }
@@ -237,4 +265,4 @@ function preflight() {
   }
 }
 
-module.exports = { preflight, missingDeps, nativeModuleBroken };
+module.exports = { preflight, missingDeps, nativeModuleBroken, requiredDeps };
diff --git a/server/test/preflight-deps.test.js b/server/test/preflight-deps.test.js
index 1d68c92..21fb951 100644
--- a/server/test/preflight-deps.test.js
+++ b/server/test/preflight-deps.test.js
@@ -90,3 +90,33 @@ test('server.js runs the preflight BEFORE requiring anything', () => {
   assert.ok(preflightAt > -1, 'server.js must run the preflight');
   assert.ok(preflightAt < firstDep, 'it must come before the first dependency, or it cannot help');
 });
+
+/*
+ * ⚠️ AN OPTIONAL DEPENDENCY IS NOT OPTIONAL ON A HOST WITH NO FALLBACK.
+ *
+ * better-sqlite3 became optional so a compiler-less host installs cleanly and drops to the built-in
+ * node:sqlite. But the built-in is Node 24 in practice — absent on 20.x, flagged off on 22.x — and
+ * this project's declared floor is 22.9. On those runtimes a missing better-sqlite3 is not a slower
+ * server, it is no server.
+ *
+ * This is not theoretical: `npm ci` on a machine that declines to run install scripts reported
+ * success, silently left no better-sqlite3 on disk, and every test that spawns the server failed
+ * with "server did not boot". Preflight has to notice and repair that.
+ */
+test('an optional dependency counts as required where node:sqlite is unavailable', () => {
+  const pkg = { dependencies: { express: '^4' }, optionalDependencies: { 'better-sqlite3': '12.9.0' } };
+
+  const withBuiltin = preflight.requiredDeps(pkg, true);
+  assert.deepEqual(withBuiltin, ['express'],
+    'on Node 24 the native driver is genuinely optional — the built-in can serve');
+
+  const withoutBuiltin = preflight.requiredDeps(pkg, false);
+  assert.deepEqual(withoutBuiltin.sort(), ['better-sqlite3', 'express'],
+    'on Node 20/22 a missing native driver means the server cannot start, so repair it');
+});
+
+test('requiredDeps copes with a package.json missing either section', () => {
+  assert.deepEqual(preflight.requiredDeps({}, false), []);
+  assert.deepEqual(preflight.requiredDeps({ optionalDependencies: { a: '1' } }, false), ['a']);
+  assert.deepEqual(preflight.requiredDeps({ dependencies: { b: '1' } }, false), ['b']);
+});