diff --git a/manifest.ts b/manifest.ts
index 0f5bf8f..3c3eaeb 100644
--- a/manifest.ts
+++ b/manifest.ts
@@ -88,13 +88,20 @@ export const manifest: PluginManifest = {
     {
       binary: 'wine',
       reason: 'Runs the game. Minesweeper X is a 32-bit Windows executable, so this host also needs i386 multiarch (`dpkg --add-architecture i386`) and the 32-bit wine package — a 64-bit-only wine cannot load it.',
-      packages: { apt: 'wine wine32:i386', dnf: 'wine', pacman: 'wine', brew: 'wine-stable' },
+      // `apt: 'wine'` alone, deliberately. The 32-bit half is `wine32:i386`, and a package name may not
+      // carry an architecture suffix or a second package — nor should it, since `dpkg --add-architecture
+      // i386` has to happen first and no package name can express that. The `reason` above carries the
+      // whole command, which is what the owner is shown when this is missing.
+      packages: { apt: 'wine', dnf: 'wine', pacman: 'wine', brew: 'wine-stable' },
       scope: 'owner',
     },
     {
       binary: 'Xvfb',
       reason: 'The virtual display the game draws on. A framebuffer with no hardware behind it, so nothing appears on any real monitor.',
-      packages: { apt: 'xvfb', dnf: 'xorg-x11-server-Xvfb', pacman: 'xorg-server-xvfb' },
+      // No `dnf` entry, and not by omission. Fedora's package is `xorg-x11-server-Xvfb` — capital X —
+      // and a manifest package name must be lowercase. Left out means "cannot be installed automatically
+      // here", which turns into an instruction to the owner rather than a wrong guess.
+      packages: { apt: 'xvfb', pacman: 'xorg-server-xvfb' },
       scope: 'owner',
     },
     {
diff --git a/sidecar/prefix.ts b/sidecar/prefix.ts
index fd0b3a1..051c528 100644
--- a/sidecar/prefix.ts
+++ b/sidecar/prefix.ts
@@ -115,12 +115,35 @@ export async function ensurePrefix(log: (line: string) => void): Promise<PrefixR
  * ── What is left ──
  *
  * `C:` alone, pointing at the prefix. The game keeps its own directory, its settings and its replays; it can
- * see nothing else. Serial and parallel device nodes go too — a 1997 puzzle game has no business holding an
- * open descriptor on `/dev/ttyS0`.
+ * see nothing else.
  *
- * Re-asserted on every start rather than only at creation, because wine recreates `z:` whenever it decides
- * the prefix needs updating — a wine package upgrade is enough, and it would restore the hole silently.
+ * ── It runs TWICE per start, and that is not belt-and-braces ──
+ *
+ * Wine rebuilds `dosdevices` when it boots a prefix it thinks needs updating, and a wine package upgrade is
+ * enough to make it think so. Observed directly: after a run, every `com*` link had come back with a fresh
+ * timestamp — so a confinement that happens only before wine starts is a confinement wine can undo.
+ *
+ * `z:` did not come back in that observation, and the device nodes are harmless. But "the dangerous one
+ * happened not to regenerate this time" is not a property to rely on, so `confineAndVerify` runs again once
+ * the game is up and says so loudly if `z:` returned. The second pass is a handful of `unlink` calls.
  */
+/**
+ * Confine, then check it held. Returns whether `z:` had to be removed a second time — which means wine
+ * regenerated it and the first pass was not enough.
+ */
+export function confineAndVerify(log: (line: string) => void): boolean {
+  const z = join(WINEPREFIX, 'dosdevices', 'z:');
+  const regenerated = existsSync(z);
+  confinePrefix();
+  if (regenerated) {
+    // Not fatal — it has just been removed again, before anything could look at the display. Worth saying
+    // out loud because it means a wine upgrade landed, and the NEXT thing to check is whether the prefix
+    // still runs the game at all.
+    log('wine regenerated the Z: drive mapping during startup; removed it again');
+  }
+  return regenerated;
+}
+
 export function confinePrefix(): void {
   const dosdevices = join(WINEPREFIX, 'dosdevices');
   if (existsSync(dosdevices)) {
diff --git a/sidecar/session.ts b/sidecar/session.ts
index 65945c9..b572e30 100644
--- a/sidecar/session.ts
+++ b/sidecar/session.ts
@@ -1,7 +1,7 @@
 import type { Subprocess } from 'bun';
 import { existsSync, rmSync } from 'node:fs';
 import { GAME_EXE, RUN_DIR, VNC_SOCKET, ensureDirs } from './paths';
-import { WINE_ENV, ensurePrefix, prefixReady } from './prefix';
+import { WINE_ENV, confineAndVerify, ensurePrefix, prefixReady } from './prefix';
 import { run, waitFor } from './run';
 
 /**
@@ -179,6 +179,11 @@ async function startInner(log: (line: string) => void): Promise<SessionStatus> {
     }
   }
 
+  // Wine has now booted the prefix, and booting it is what can restore `Z:`. The confinement in
+  // `ensurePrefix` happens before that, so on its own it would be undone by exactly the event it exists to
+  // survive. See `confineAndVerify`.
+  confineAndVerify(log);
+
   // ── the display server ──
   if (!alive(vnc)) {
     // A socket left by a crashed run refuses to bind. Removing it is safe: nothing else may write here.