diff --git a/README.md b/README.md
index 849022f..e3962d3 100644
--- a/README.md
+++ b/README.md
@@ -47,9 +47,11 @@ CYD_FIRMWARE_ROOT=C:\Users\dsx2016\Desktop\codes\cyd
 
 After rebuilding a project, run its `firmware\export_from_build.ps1`, then click **Refresh**.
 
-## Extending a firmware (media / docs)
+## Extending a firmware (HTML UI preview / docs)
 
-Create `meta.json` beside the `.bin` files:
+Preferred card preview: **`media/preview.html`** — HTML recreation of the on-device LVGL UI (320×240). Auto-detected if present.
+
+Optional `meta.json` beside the `.bin` files:
 
 ```json
 {
@@ -59,19 +61,18 @@ Create `meta.json` beside the `.bin` files:
   "description": "Longer detail text",
   "tags": ["pomodoro", "touch"],
   "media": {
-    "cover": "media/cover.webp",
-    "animation": "media/preview.gif",
+    "preview": "media/preview.html",
     "video": "media/demo.mp4",
     "docs": "docs/README.md"
   }
 }
 ```
 
-- Relative media paths are served via `/api/firmware/.../media/...` (only if the file exists).
+- Media paths are served via `/api/firmware/.../media/...` (only if the file exists).
 - `docs` may also be an `https://` URL.
 - `boardId` values: `esp32-2432s028` (active), `esp32-2432s024`, `esp32-3248s035`, `esp32-s3-touch` (UI reserved).
 
-Without `meta.json`, the catalog still works from `VERSION.txt`.
+Without `meta.json`, the catalog still works from `VERSION.txt` + auto `media/preview.html`.
 
 ## Public deploy (Docker + Caddy)
 
diff --git a/components/firmware-card.tsx b/components/firmware-card.tsx
index 371559e..9e9d848 100644
--- a/components/firmware-card.tsx
+++ b/components/firmware-card.tsx
@@ -1,48 +1,10 @@
 "use client";
 
-import { Film, FileText, ImageIcon } from "lucide-react";
+import { FileText, LayoutTemplate } from "lucide-react";
 import type { FirmwareInfo } from "@/lib/firmware";
 import { formatBytes, cn } from "@/lib/utils";
 import { Badge } from "@/components/ui/badge";
-
-function MediaSlot({ fw, active }: { fw: FirmwareInfo; active: boolean }) {
-  const src = fw.media.animation || fw.media.cover;
-  if (src) {
-    return (
-      // Dynamic firmware media URLs — next/image needs remotePatterns per host
-      // eslint-disable-next-line @next/next/no-img-element -- local API / arbitrary media
-      <img
-        src={src}
-        alt=""
-        className="h-full w-full object-cover transition-transform duration-500 group-hover:scale-[1.03]"
-      />
-    );
-  }
-
-  const initials = fw.name
-    .replace(/[^A-Za-z0-9\u4e00-\u9fff]+/g, " ")
-    .trim()
-    .split(/\s+/)
-    .slice(0, 2)
-    .map((w) => w[0]?.toUpperCase() ?? "")
-    .join("");
-
-  return (
-    <div
-      className={cn(
-        "flex h-full w-full flex-col items-center justify-center gap-2 bg-[radial-gradient(ellipse_at_30%_20%,rgba(240,197,10,0.18),transparent_55%),linear-gradient(160deg,#1a1610,#0e0c09)]",
-        active && "from-[rgba(240,197,10,0.22)]"
-      )}
-    >
-      <span className="font-[family-name:var(--font-display)] text-3xl font-extrabold tracking-tight text-[var(--accent-hot)]/80">
-        {initials || "FW"}
-      </span>
-      <span className="text-[0.65rem] uppercase tracking-[0.14em] text-[var(--muted)]">
-        preview soon
-      </span>
-    </div>
-  );
-}
+import { FirmwarePreview } from "@/components/firmware-preview";
 
 export function FirmwareCard({
   fw,
@@ -53,9 +15,8 @@ export function FirmwareCard({
   active: boolean;
   onSelect: () => void;
 }) {
-  const hasVideo = Boolean(fw.media.video);
+  const hasPreview = Boolean(fw.media.preview);
   const hasDocs = Boolean(fw.media.docs);
-  const hasCover = Boolean(fw.media.cover || fw.media.animation);
 
   return (
     <button
@@ -71,16 +32,11 @@ export function FirmwareCard({
       )}
     >
       <div className="relative aspect-[16/10] w-full overflow-hidden border-b border-[var(--line)]">
-        <MediaSlot fw={fw} active={active} />
-        <div className="absolute bottom-2 left-2 flex gap-1">
-          {hasCover && (
+        <FirmwarePreview fw={fw} />
+        <div className="pointer-events-none absolute bottom-2 left-2 flex gap-1">
+          {hasPreview && (
             <span className="rounded bg-black/55 p-1 text-[var(--ink)] backdrop-blur-sm">
-              <ImageIcon className="size-3" aria-hidden />
-            </span>
-          )}
-          {hasVideo && (
-            <span className="rounded bg-black/55 p-1 text-[var(--ink)] backdrop-blur-sm">
-              <Film className="size-3" aria-hidden />
+              <LayoutTemplate className="size-3" aria-hidden />
             </span>
           )}
           {hasDocs && (
@@ -91,7 +47,7 @@ export function FirmwareCard({
         </div>
         <Badge
           variant="muted"
-          className="absolute bottom-2 right-2 bg-black/55 text-[0.65rem] backdrop-blur-sm"
+          className="pointer-events-none absolute bottom-2 right-2 bg-black/55 text-[0.65rem] backdrop-blur-sm"
         >
           {formatBytes(fw.size)}
         </Badge>
diff --git a/components/firmware-detail.tsx b/components/firmware-detail.tsx
index cb66222..374cec6 100644
--- a/components/firmware-detail.tsx
+++ b/components/firmware-detail.tsx
@@ -6,6 +6,7 @@ import type { FirmwareInfo } from "@/lib/firmware";
 import { formatBytes } from "@/lib/utils";
 import { Badge } from "@/components/ui/badge";
 import { EspWebInstall } from "@/components/esp-web-install";
+import { FirmwarePreview } from "@/components/firmware-preview";
 
 export function FirmwareDetail({
   fw,
@@ -24,8 +25,6 @@ export function FirmwareDetail({
     );
   }
 
-  const preview = fw.media.video || fw.media.animation || fw.media.cover;
-
   return (
     <aside className="sticky top-4 flex flex-col overflow-hidden rounded-[14px] border border-[var(--line)] bg-[color-mix(in_srgb,var(--bg-elev)_92%,transparent)] backdrop-blur-sm">
       <div className="border-b border-[var(--line)] px-4 py-3">
@@ -37,32 +36,26 @@ export function FirmwareDetail({
         </h3>
       </div>
 
-      <div className="aspect-video w-full border-b border-[var(--line)] bg-black/40">
-        {fw.media.video ? (
+      <div className="aspect-[4/3] w-full border-b border-[var(--line)] bg-black/40">
+        {fw.media.preview ? (
+          <FirmwarePreview fw={fw} />
+        ) : fw.media.video ? (
           <video
             key={fw.media.video}
             className="h-full w-full object-cover"
             controls
             playsInline
             preload="metadata"
-            poster={fw.media.cover || undefined}
           >
             <source src={fw.media.video} />
           </video>
-        ) : preview ? (
-          // eslint-disable-next-line @next/next/no-img-element
-          <img
-            src={preview}
-            alt=""
-            className="h-full w-full object-cover"
-          />
         ) : (
           <div className="flex h-full flex-col items-center justify-center gap-1 px-4 text-center">
             <p className="m-0 text-sm text-[var(--muted)]">
               {t("firmware.mediaPlaceholder")}
             </p>
             <p className="m-0 text-xs text-[var(--muted)] opacity-70">
-              meta.json → media.cover / animation / video
+              media/preview.html
             </p>
           </div>
         )}
diff --git a/components/firmware-preview.tsx b/components/firmware-preview.tsx
new file mode 100644
index 0000000..8fed5ae
--- /dev/null
+++ b/components/firmware-preview.tsx
@@ -0,0 +1,52 @@
+"use client";
+
+import type { FirmwareInfo } from "@/lib/firmware";
+import { cn } from "@/lib/utils";
+
+/** Renders HTML on-device UI mock (preferred) — never uses raster covers. */
+export function FirmwarePreview({
+  fw,
+  className,
+  title,
+}: {
+  fw: FirmwareInfo;
+  className?: string;
+  title?: string;
+}) {
+  if (fw.media.preview) {
+    return (
+      <iframe
+        title={title || `${fw.name} UI preview`}
+        src={fw.media.preview}
+        className={cn("h-full w-full border-0 bg-[#0A1016]", className)}
+        loading="lazy"
+        sandbox="allow-scripts"
+        tabIndex={-1}
+      />
+    );
+  }
+
+  const initials = fw.name
+    .replace(/[^A-Za-z0-9\u4e00-\u9fff]+/g, " ")
+    .trim()
+    .split(/\s+/)
+    .slice(0, 2)
+    .map((w) => w[0]?.toUpperCase() ?? "")
+    .join("");
+
+  return (
+    <div
+      className={cn(
+        "flex h-full w-full flex-col items-center justify-center gap-2 bg-[radial-gradient(ellipse_at_30%_20%,rgba(240,197,10,0.18),transparent_55%),linear-gradient(160deg,#1a1610,#0e0c09)]",
+        className
+      )}
+    >
+      <span className="font-[family-name:var(--font-display)] text-3xl font-extrabold tracking-tight text-[var(--accent-hot)]/80">
+        {initials || "FW"}
+      </span>
+      <span className="text-[0.65rem] uppercase tracking-[0.14em] text-[var(--muted)]">
+        HTML preview soon
+      </span>
+    </div>
+  );
+}
diff --git a/components/ui-preview.tsx b/components/ui-preview.tsx
new file mode 100644
index 0000000..41d7918
--- /dev/null
+++ b/components/ui-preview.tsx
@@ -0,0 +1,27 @@
+"use client";
+
+import { cn } from "@/lib/utils";
+
+/** Scales an on-device HTML mock (320×240) into the card / detail media slot. */
+export function UiPreview({
+  src,
+  className,
+  title,
+}: {
+  src: string;
+  className?: string;
+  title?: string;
+}) {
+  return (
+    <div className={cn("relative h-full w-full overflow-hidden bg-[#0a0806]", className)}>
+      <iframe
+        src={src}
+        title={title || "Firmware UI preview"}
+        className="pointer-events-none absolute inset-0 h-full w-full border-0"
+        loading="lazy"
+        sandbox="allow-scripts"
+        tabIndex={-1}
+      />
+    </div>
+  );
+}
diff --git a/lib/firmware.ts b/lib/firmware.ts
index ecce58b..1dbfc0b 100644
--- a/lib/firmware.ts
+++ b/lib/firmware.ts
@@ -18,6 +18,8 @@ export const FLASH_PARTS = [
 
 /** Optional rich metadata: place meta.json next to the .bin files. */
 export type FirmwareMedia = {
+  /** HTML UI mock of the on-device screen (preferred card preview). */
+  preview: string | null;
   cover: string | null;
   animation: string | null;
   video: string | null;
@@ -54,6 +56,7 @@ type MetaJson = {
   board?: string;
   flash_size?: string;
   media?: {
+    preview?: string;
     cover?: string;
     animation?: string;
     video?: string;
@@ -165,6 +168,9 @@ function buildFirmwareInfo(
       Object.entries(versionMeta).filter(([k]) => !reserved.has(k))
     ),
     media: {
+      preview:
+        mediaUrl(project, variant, dir, json?.media?.preview) ||
+        mediaUrl(project, variant, dir, "media/preview.html"),
       cover: mediaUrl(project, variant, dir, json?.media?.cover),
       animation: mediaUrl(project, variant, dir, json?.media?.animation),
       video: mediaUrl(project, variant, dir, json?.media?.video),
diff --git a/messages/en.json b/messages/en.json
index f57d410..4a30966 100644
--- a/messages/en.json
+++ b/messages/en.json
@@ -36,7 +36,7 @@
     "noneSelected": "Select a firmware card to see details and flash",
     "selectedLabel": "Selected",
     "docs": "Documentation",
-    "mediaPlaceholder": "Animation / video / cover will appear here"
+    "mediaPlaceholder": "On-device HTML UI preview will appear here"
   },
   "install": {
     "cta": "Connect & flash",
diff --git a/messages/zh.json b/messages/zh.json
index c5f99b2..2a1ba72 100644
--- a/messages/zh.json
+++ b/messages/zh.json
@@ -36,7 +36,7 @@
     "noneSelected": "点选固件卡片查看详情并刷写",
     "selectedLabel": "已选",
     "docs": "文档",
-    "mediaPlaceholder": "动画 / 视频 / 封面将显示在这里"
+    "mediaPlaceholder": "设备界面 HTML 预览将显示在这里"
   },
   "install": {
     "cta": "连接并刷写",