diff --git a/packages/app/resources/strings.json b/packages/app/resources/strings.json
index ac990c0..ec1f4ab 100644
--- a/packages/app/resources/strings.json
+++ b/packages/app/resources/strings.json
@@ -665,6 +665,7 @@
 	"This TV runs Tizen {version}. Games require Tizen 5 or newer.": "This TV runs Tizen {version}. Games require Tizen 5 or newer.",
 	"This TV runs webOS {version}. Games require webOS 5 or newer.": "This TV runs webOS {version}. Games require webOS 5 or newer.",
 	"This core has no adjustable options.": "This core has no adjustable options.",
+	"This game is too large to run on this TV.": "This game is too large to run on this TV.",
 	"Thumb": "Thumb",
 	"Timeout": "Timeout",
 	"Tizen Version": "Tizen Version",
diff --git a/packages/app/src/services/gamesApi.js b/packages/app/src/services/gamesApi.js
index a094235..cafe576 100644
--- a/packages/app/src/services/gamesApi.js
+++ b/packages/app/src/services/gamesApi.js
@@ -1,8 +1,11 @@
 // Client for the Moonbase plugin retro-games (EmulatorJS) endpoints under /Moonfin/Games.
 // JSON calls route through platformFetch (the webOS Let's-Encrypt TLS proxy) so metadata and
-// the settings blob work on old webOS. ROM/BIOS and the binary save state use native fetch and
-// a Blob URL (the proxy is text-only), so they inherit the same old-webOS+LE limitation as
-// video playback; cores are loaded from the trusted-cert CDN and work everywhere.
+// the settings blob work on old webOS. A ROM is served as a direct server URL carrying the
+// token in the query, which lets EmulatorJS stream the file instead of the app buffering it,
+// and falls back to a Blob URL where that request does not get through. BIOS files and the
+// binary save state always use native fetch and a Blob URL (the proxy is text-only), so they
+// inherit the same old-webOS+LE limitation as video playback. Cores load from the
+// trusted-cert CDN and work everywhere.
 
 import {getServerUrl, getAuthHeader, getApiKey, getTokenParam} from './jellyfinApi';
 import {platformFetch} from './secureFetch';
@@ -49,8 +52,31 @@ export const gameThumbUrl = (libraryId, gameId, kind = 'boxart') => {
 	return `${base()}/Moonfin/Games/${enc(libraryId)}/Thumb/${enc(gameId)}?type=${enc(kind)}${auth}`;
 };
 
-// ROM / BIOS as a same-origin Blob URL (avoids CORS; EmulatorJS fetches the blob directly).
-const blobUrl = async (path) => {
+// The largest ROM a TV will take. Buffering is what kills it, since the response, the Blob and
+// the copy EmulatorJS keeps all sit in the WebView heap at once and past this the app is killed
+// part-way through loading. Measured on a device rather than taken from a published limit, so
+// it is deliberately conservative.
+const MAX_ROM_BYTES = 48 * 1024 * 1024;
+
+const romTooLarge = (bytes) => {
+	const err = new Error('rom-too-large');
+	err.romTooLarge = true;
+	err.totalBytes = bytes;
+	return err;
+};
+
+// Drops a response once its headers have been read, so nothing is left streaming a body that
+// will never be used. Older WebViews have no res.body, hence the guard.
+const discardBody = (res) => {
+	try {
+		if (res.body && res.body.cancel) res.body.cancel();
+	} catch (e) { /* already closed */ }
+};
+
+// ROM / BIOS as a same-origin Blob URL, which avoids CORS since EmulatorJS fetches the blob
+// directly. maxBytes refuses an oversized file before it is buffered, because the failure
+// happens inside res.blob(), where the TV can take the whole app down with it.
+const blobUrl = async (path, maxBytes) => {
 	const res = await fetchWithTimeout(`${base()}/Moonfin/Games/${path}`, {
 		headers: authHeaders()
 	}, 60000);
@@ -59,15 +85,61 @@ const blobUrl = async (path) => {
 		err.status = res.status;
 		throw err;
 	}
+	const expected = Number(res.headers.get('content-length')) || null;
+	if (maxBytes && expected && expected > maxBytes) {
+		discardBody(res);
+		throw romTooLarge(expected);
+	}
 	const blob = await res.blob();
 	return URL.createObjectURL(blob);
 };
 
-export const getRomBlobUrl = (libraryId, gameId) =>
-	blobUrl(`${enc(libraryId)}/Rom/${enc(gameId)}`);
+const getRomBlobUrl = (libraryId, gameId) =>
+	blobUrl(`${enc(libraryId)}/Rom/${enc(gameId)}`, MAX_ROM_BYTES);
+// A BIOS is a few hundred kilobytes at most, so there is nothing to refuse on size.
 export const getBiosBlobUrl = (libraryId, biosId) =>
 	blobUrl(`${enc(libraryId)}/Bios/${enc(biosId)}`);
 
+// The ROM endpoint takes the token in the query, which is how EmulatorJS's own XHR
+// authenticates. Null when there is no token to put there.
+const romDirectUrl = (libraryId, gameId) => {
+	const token = getApiKey();
+	if (!token) return null;
+	return `${base()}/Moonfin/Games/${enc(libraryId)}/Rom/${enc(gameId)}?${getTokenParam()}=${enc(token)}`;
+};
+
+// Asks for the first byte only. The endpoint streams with range processing on, so a 206 comes
+// back carrying the full size in Content-Range and this costs one byte instead of the ROM.
+const probeRom = async (url) => {
+	try {
+		const res = await fetchWithTimeout(url, {headers: {Range: 'bytes=0-0'}}, 15000);
+		discardBody(res);
+		if (res.status !== 206 && !res.ok) return {ok: false, totalBytes: null};
+		const range = res.headers.get('content-range');
+		const total = range && range.split('/')[1];
+		// Content-Length on a 206 describes the one byte asked for, so it only stands in for the
+		// size when the server ignored the range and answered with the whole file.
+		const whole = res.status === 206 ? null : Number(res.headers.get('content-length'));
+		return {ok: true, totalBytes: Number(total) || whole || null};
+	} catch (e) {
+		return {ok: false, totalBytes: null};
+	}
+};
+
+// Returns {url, isBlob} for a game's ROM. The direct URL is preferred, because EmulatorJS then
+// streams the file itself and no second copy passes through the app. The Blob URL covers the
+// platforms where a plain fetch to the server does not get through, such as old webOS behind
+// Let's Encrypt, and isBlob tells the caller whether it has a URL to revoke afterwards.
+export const getRomUrl = async (libraryId, gameId) => {
+	const direct = romDirectUrl(libraryId, gameId);
+	const probe = direct ? await probeRom(direct) : {ok: false, totalBytes: null};
+	if (probe.totalBytes && probe.totalBytes > MAX_ROM_BYTES) throw romTooLarge(probe.totalBytes);
+	if (probe.ok) return {url: direct, isBlob: false};
+	// A failed probe leaves the size unknown, so getRomBlobUrl applies the same ceiling from
+	// Content-Length. Falling back must not mean skipping the check.
+	return {url: await getRomBlobUrl(libraryId, gameId), isBlob: true};
+};
+
 // Save state (binary) keyed per game. Returns null when none exists (404).
 export const getStateBytes = async (gameId) => {
 	try {
diff --git a/packages/app/src/services/gamesApi.test.js b/packages/app/src/services/gamesApi.test.js
new file mode 100644
index 0000000..a1dcd9c
--- /dev/null
+++ b/packages/app/src/services/gamesApi.test.js
@@ -0,0 +1,99 @@
+import {getRomUrl} from './gamesApi';
+import {fetchWithTimeout} from '../utils/fetchTimeout';
+
+let mockToken = 'key';
+
+jest.mock('../utils/fetchTimeout', () => ({fetchWithTimeout: jest.fn()}));
+jest.mock('./secureFetch', () => ({platformFetch: jest.fn()}));
+jest.mock('./jellyfinApi', () => ({
+	getServerUrl: () => 'https://server',
+	getAuthHeader: () => 'MediaBrowser Token="t"',
+	getApiKey: () => mockToken,
+	getTokenParam: () => 'ApiKey'
+}));
+
+const MB = 1024 * 1024;
+
+const response = ({status = 200, headers = {}} = {}) => {
+	const lower = {};
+	Object.keys(headers).forEach((k) => { lower[k.toLowerCase()] = headers[k]; });
+	return {
+		status,
+		ok: status >= 200 && status < 300,
+		headers: {get: (name) => (name.toLowerCase() in lower ? lower[name.toLowerCase()] : null)},
+		body: {cancel: jest.fn()},
+		blob: () => Promise.resolve({size: 1})
+	};
+};
+
+// A 206 to the one-byte probe, reporting `total` as the size of the whole ROM.
+const probeOf = (total) => response({
+	status: 206,
+	headers: {'content-range': `bytes 0-0/${total}`, 'content-length': '1'}
+});
+
+describe('getRomUrl', () => {
+	beforeEach(() => {
+		fetchWithTimeout.mockReset();
+		mockToken = 'key';
+		global.URL.createObjectURL = jest.fn(() => 'blob:rom');
+	});
+
+	test('serves the direct url when the probed size is under the ceiling', async () => {
+		fetchWithTimeout.mockResolvedValueOnce(probeOf(4 * MB));
+
+		const rom = await getRomUrl('lib', 'game');
+
+		expect(rom.isBlob).toBe(false);
+		expect(rom.url).toBe('https://server/Moonfin/Games/lib/Rom/game?ApiKey=key');
+		// Only the probe went out, so nothing was buffered.
+		expect(fetchWithTimeout).toHaveBeenCalledTimes(1);
+	});
+
+	test('refuses a rom past the ceiling instead of buffering it', async () => {
+		fetchWithTimeout.mockResolvedValueOnce(probeOf(96 * MB));
+
+		await expect(getRomUrl('lib', 'game')).rejects.toMatchObject({romTooLarge: true});
+		expect(fetchWithTimeout).toHaveBeenCalledTimes(1);
+	});
+
+	test('reads the size off Content-Range, not the one byte the probe asked for', async () => {
+		fetchWithTimeout.mockResolvedValueOnce(response({status: 206, headers: {'content-length': '1'}}));
+
+		const rom = await getRomUrl('lib', 'game');
+
+		// No Content-Range means the size stayed unknown, so the 1 must not pass as the total.
+		expect(rom).toEqual({url: 'https://server/Moonfin/Games/lib/Rom/game?ApiKey=key', isBlob: false});
+	});
+
+	test('falls back to a blob url when the probe cannot reach the server', async () => {
+		fetchWithTimeout
+			.mockRejectedValueOnce(new Error('network'))
+			.mockResolvedValueOnce(response({headers: {'content-length': String(4 * MB)}}));
+
+		const rom = await getRomUrl('lib', 'game');
+
+		expect(rom).toEqual({url: 'blob:rom', isBlob: true});
+	});
+
+	test('applies the ceiling to the blob fallback, where the size is only known from the headers', async () => {
+		fetchWithTimeout
+			.mockRejectedValueOnce(new Error('network'))
+			.mockResolvedValueOnce(response({headers: {'content-length': String(96 * MB)}}));
+
+		await expect(getRomUrl('lib', 'game')).rejects.toMatchObject({romTooLarge: true});
+		expect(global.URL.createObjectURL).not.toHaveBeenCalled();
+	});
+
+	test('goes straight to the blob when there is no token to put in the query', async () => {
+		mockToken = null;
+		fetchWithTimeout.mockResolvedValueOnce(response({headers: {'content-length': String(2 * MB)}}));
+
+		const rom = await getRomUrl('lib', 'game');
+
+		expect(rom.isBlob).toBe(true);
+		// The probe is skipped entirely, so the blob fetch is the first request.
+		expect(fetchWithTimeout).toHaveBeenCalledTimes(1);
+		expect(fetchWithTimeout.mock.calls[0][0]).toBe('https://server/Moonfin/Games/lib/Rom/game');
+	});
+});
diff --git a/packages/app/src/utils/emulatorjs.js b/packages/app/src/utils/emulatorjs.js
index 43a244d..8d3f644 100644
--- a/packages/app/src/utils/emulatorjs.js
+++ b/packages/app/src/utils/emulatorjs.js
@@ -1,16 +1,26 @@
-// Same-origin EmulatorJS control glue. Ports the Moonbase plugin player.html script so the
-// enact app drives EmulatorJS directly (no iframe / postMessage). Loader + WASM cores come
-// from the trusted-cert CDN (works on old webOS); the ROM/BIOS are Blob URLs the app already
-// fetched. Threads are off (no cross-origin isolation on app:// / file://), so single-threaded
-// cores only.
+// EmulatorJS control glue. Ports the Moonbase plugin player.html script so the enact app
+// drives EmulatorJS directly (no iframe / postMessage). Loader + WASM cores come from the
+// trusted-cert CDN and work on old webOS. The ROM is either a direct server URL EmulatorJS
+// streams itself or a Blob URL the app already fetched, and the BIOS is always a Blob URL.
+// Threads are off (no cross-origin isolation on app:// / file://), so single-threaded cores only.
 
 import $L from '@enact/i18n/$L';
 
+import serverLogger from '../services/serverLogger';
 import {isWebOS, isTizen} from '../platform';
 
+const logGames = (message, context) =>
+	serverLogger.debug(serverLogger.LOG_CATEGORIES.APP, `[Games] ${message}`, context);
+const logGamesError = (message, context) =>
+	serverLogger.error(serverLogger.LOG_CATEGORIES.APP, `[Games] ${message}`, context, false);
+
 const CDN = 'https://cdn.emulatorjs.org/stable/data/';
 
 let loaderScript = null;
+// The config loader.js built and the class it constructed. Both outlive a teardown, so a later
+// launch can build an emulator straight away instead of downloading the bundle again.
+let loadedConfig = null;
+let EmulatorCtor = null;
 
 // EmulatorJS cores are WebAssembly, which needs Chromium 57+. Older WebViews (webOS 4 and
 // below at Chrome 53, Tizen 4 and below at Chrome 56) lack it entirely, so games can't run
@@ -63,12 +73,47 @@ export const unsupportedMessage = () => {
 // so reject after this timeout and let the caller show an error instead of hanging.
 const READY_TIMEOUT = 40000;
 
+// EmulatorJS writes what it is doing into its own status element, which is the only clue to
+// where a boot stalled once it stops making progress.
+const emulatorStatusText = () => {
+	const emu = window.EJS_emulator;
+	return (emu && emu.textElem && emu.textElem.innerText) || null;
+};
+
 // Starts EmulatorJS in the element matching `selector` and resolves once the core is ready.
 export const startEmulator = ({selector, core, gameUrl, biosUrl, gameName, settingsJson}) =>
 	new Promise((resolve, reject) => {
 		if (settingsJson) {
 			try { window.localStorage.setItem('ejs-settings', settingsJson); } catch (e) { /* ignore */ }
 		}
+
+		const startedAt = Date.now();
+		// EmulatorJS reports a failed boot by never firing ready, so the reason only shows up as
+		// an uncaught error. Watch the window for as long as the boot runs to keep it.
+		const onWindowError = (ev) => logGamesError('window error during emulator boot', {
+			core,
+			message: ev.message || String(ev.error || ''),
+			source: ev.filename ? `${ev.filename}:${ev.lineno}` : null
+		});
+		const onRejection = (ev) => logGamesError('unhandled rejection during emulator boot', {
+			core,
+			reason: String((ev.reason && (ev.reason.message || ev.reason)) || '')
+		});
+		window.addEventListener('error', onWindowError);
+		window.addEventListener('unhandledrejection', onRejection);
+		const stopWatching = () => {
+			window.removeEventListener('error', onWindowError);
+			window.removeEventListener('unhandledrejection', onRejection);
+		};
+
+		// A TV that runs out of memory mid-boot takes the app with it and never reaches the
+		// timeout below, so this line is the last thing a report will show.
+		logGames('starting emulator', {
+			core,
+			gameName,
+			bios: Boolean(biosUrl),
+			blobRom: String(gameUrl || '').startsWith('blob:')
+		});
 		window.EJS_player = selector;
 		window.EJS_core = core;
 		window.EJS_gameUrl = gameUrl;
@@ -81,11 +126,63 @@ export const startEmulator = ({selector, core, gameUrl, biosUrl, gameName, setti
 		// No touch screen on TV; keep the on-screen pad off.
 		window.EJS_defaultOptions = Object.assign({}, window.EJS_defaultOptions, {'virtual-gamepad': 'disabled'});
 
-		const timer = setTimeout(() => reject(new Error('emulator-load-timeout')), READY_TIMEOUT);
-		window.EJS_ready = () => { clearTimeout(timer); resolve(); };
+		let reused = false;
+		const timer = setTimeout(() => {
+			stopWatching();
+			// Whatever was cached built an emulator that never started, so drop it and let the
+			// next launch go back through the loader rather than repeat the same dead boot.
+			loadedConfig = null;
+			EmulatorCtor = null;
+			logGamesError('emulator never became ready', {reused, emulatorStatus: emulatorStatusText()});
+			reject(new Error('emulator-load-timeout'));
+		}, READY_TIMEOUT);
+		window.EJS_ready = () => {
+			clearTimeout(timer);
+			stopWatching();
+			loadedConfig = (window.EJS_emulator && window.EJS_emulator.config) || loadedConfig;
+			EmulatorCtor = (window.EJS_emulator && window.EJS_emulator.constructor) || EmulatorCtor;
+			logGames('emulator ready', {core, ms: Date.now() - startedAt, reused});
+			resolve();
+		};
+
+		// Once the bundle is parsed a later launch can build the emulator from the cached class
+		// instead of downloading the loader again. loader.js hooks the ready callback up itself
+		// with emulator.on('ready', ...) rather than passing it in the config, so this path has
+		// to do the same or the promise above could only ever settle by timing out.
+		if (loadedConfig && EmulatorCtor && typeof EmulatorCtor.prototype?.on === 'function') {
+			try {
+				const config = Object.assign({}, loadedConfig, {
+					gameUrl,
+					system: core,
+					biosUrl: biosUrl || '',
+					gameName: gameName || '',
+					dataPath: CDN,
+					startOnLoad: true,
+					threads: false,
+					defaultOptions: window.EJS_defaultOptions
+				});
+				const emulator = new EmulatorCtor(selector, config);
+				window.EJS_emulator = emulator;
+				window.EJS_adBlocked = (url, del) => emulator.adBlocked(url, del);
+				emulator.on('ready', window.EJS_ready);
+				reused = true;
+				return;
+			} catch (e) {
+				// Once the cached pair has thrown it is not worth trusting again this session.
+				loadedConfig = null;
+				EmulatorCtor = null;
+				logGamesError('could not build the emulator from the cached class', {message: e.message || String(e)});
+			}
+		}
 
 		loaderScript = document.createElement('script');
 		loaderScript.src = CDN + 'loader.js';
+		// Without this the promise sits on the full timeout when the CDN is simply unreachable.
+		loaderScript.onerror = () => {
+			clearTimeout(timer);
+			stopWatching();
+			reject(new Error('emulator-loader-unreachable'));
+		};
 		document.body.appendChild(loaderScript);
 	});
 
@@ -168,6 +265,7 @@ export const destroyEmulator = () => {
 	}
 	loaderScript = null;
 	['EJS_emulator', 'EJS_player', 'EJS_core', 'EJS_gameUrl', 'EJS_biosUrl', 'EJS_gameName',
-		'EJS_pathtodata', 'EJS_startOnLoaded', 'EJS_threads', 'EJS_ready', 'EJS_defaultOptions']
+		'EJS_pathtodata', 'EJS_startOnLoaded', 'EJS_threads', 'EJS_ready', 'EJS_defaultOptions',
+		'EJS_adBlocked']
 		.forEach((k) => { try { delete window[k]; } catch (e) { /* ignore */ } });
 };
diff --git a/packages/app/src/views/GamePlayer/GamePlayer.js b/packages/app/src/views/GamePlayer/GamePlayer.js
index 353e605..24d2f6b 100644
--- a/packages/app/src/views/GamePlayer/GamePlayer.js
+++ b/packages/app/src/views/GamePlayer/GamePlayer.js
@@ -7,6 +7,7 @@ import SpotlightContainerDecorator from '@enact/spotlight/SpotlightContainerDeco
 import AdminMessageDialog from '../../components/AdminMessageDialog';
 import LoadingSpinner from '../../components/LoadingSpinner';
 import * as gamesApi from '../../services/gamesApi';
+import serverLogger from '../../services/serverLogger';
 import {initVideo, keepScreenOn, setupVisibilityHandler} from '../../services/video';
 import * as ejs from '../../utils/emulatorjs';
 
@@ -66,13 +67,14 @@ const GamePlayer = ({library, game, startFresh, onBack, backHandlerRef}) => {
 		const libraryId = library?.Id;
 		(async () => {
 			try {
-				const [romUrl, settingsJson, existing] = await Promise.all([
-					gamesApi.getRomBlobUrl(libraryId, game.id),
+				const [rom, settingsJson, existing] = await Promise.all([
+					gamesApi.getRomUrl(libraryId, game.id),
 					gamesApi.getSettingsBlob(),
 					startFresh ? Promise.resolve(null) : gamesApi.getStateBytes(game.id)
 				]);
 				if (cancelled) return;
-				blobs.current.push(romUrl);
+				const {url: romUrl, isBlob} = rom;
+				if (isBlob) blobs.current.push(romUrl);
 				let biosUrl;
 				if (game.bios && game.bios.length) {
 					biosUrl = await gamesApi.getBiosBlobUrl(libraryId, game.bios[0].id);
@@ -92,7 +94,17 @@ const GamePlayer = ({library, game, startFresh, onBack, backHandlerRef}) => {
 				if (existing) { try { ejs.loadState(existing); } catch (e) { /* ignore */ } }
 				setReady(true);
 			} catch (e) {
-				if (!cancelled) setError(e.status === 404 ? $L('Game file not found.') : $L('Could not start this game on this device.'));
+				// Backing out mid-load lands here too, and that is not worth reporting.
+				if (cancelled) return;
+				serverLogger.error(serverLogger.LOG_CATEGORIES.APP, '[Games] could not start game', {
+					core: game.core,
+					system: game.system,
+					status: e.status || null,
+					totalBytes: e.totalBytes || null,
+					message: e.message || String(e)
+				}, false);
+				if (e.romTooLarge) setError($L('This game is too large to run on this TV.'));
+				else setError(e.status === 404 ? $L('Game file not found.') : $L('Could not start this game on this device.'));
 			}
 		})();
 		return () => {
diff --git a/packages/app/src/views/Games/Games.js b/packages/app/src/views/Games/Games.js
index e0c89da..a249abc 100644
--- a/packages/app/src/views/Games/Games.js
+++ b/packages/app/src/views/Games/Games.js
@@ -80,7 +80,9 @@ const Games = ({library, onSelectGame, onHome, backHandlerRef}) => {
 	return (
 		<div className={css.root}>
 			<h1 className={css.heading}>{library?.Name || $L('Games')}</h1>
-			<Scroller className={css.scroller} focusableScrollbar="byEnter">
+			{/* A focusable scrollbar sits in the way once the library is long enough to scroll,
+			    taking the focus on the way down instead of letting it reach the next row. */}
+			<Scroller className={css.scroller}>
 				{rows.map((system) => {
 					const games = gamesBySystem[system.id] || [];
 					return (