diff --git a/app/src/main/java/eu/kanade/tachiyomi/source/online/all/MergedSource.kt b/app/src/main/java/eu/kanade/tachiyomi/source/online/all/MergedSource.kt
index 804b37e2f..2a5017680 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/source/online/all/MergedSource.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/source/online/all/MergedSource.kt
@@ -19,6 +19,8 @@ import exh.MERGED_SOURCE_ID
 import exh.merged.sql.models.MergedMangaReference
 import exh.util.asFlow
 import exh.util.await
+import exh.util.awaitSingle
+import exh.util.awaitSingleOrNull
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.asFlow
@@ -28,10 +30,10 @@ import kotlinx.coroutines.flow.flatMapMerge
 import kotlinx.coroutines.flow.flow
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
-import kotlinx.coroutines.flow.single
-import kotlinx.coroutines.flow.singleOrNull
+import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withContext
 import okhttp3.Response
+import rx.Observable
 import uy.kohesive.injekt.injectLazy
 
 class MergedSource : SuspendHttpSource() {
@@ -83,14 +85,13 @@ class MergedSource : SuspendHttpSource() {
         }
     }
 
-    fun getChaptersFromDB(manga: Manga, editScanlators: Boolean = false, dedupe: Boolean = true): Flow<List<Chapter>> {
+    fun getChaptersFromDB(manga: Manga, editScanlators: Boolean = false, dedupe: Boolean = true): Observable<List<Chapter>> {
         // TODO more chapter dedupe
         return db.getChaptersByMergedMangaId(manga.id!!).asRxObservable()
-            .asFlow()
             .map { chapterList ->
-                val mangaReferences = withContext(Dispatchers.IO) { db.getMergedMangaReferences(manga.id!!).await() }
-                val sources = mangaReferences.map { sourceManager.getOrStub(it.mangaSourceId) to it.mangaId }
+                val mangaReferences = runBlocking(Dispatchers.IO) { db.getMergedMangaReferences(manga.id!!).await() } ?: emptyList()
                 if (editScanlators) {
+                    val sources = mangaReferences.map { sourceManager.getOrStub(it.mangaSourceId) to it.mangaId }
                     chapterList.onEach { chapter ->
                         val source = sources.firstOrNull { chapter.manga_id == it.second }?.first
                         if (source != null) {
@@ -135,7 +136,7 @@ class MergedSource : SuspendHttpSource() {
                 fetchChaptersAndSync(manga, downloadChapters).collect()
             }
             emit(
-                getChaptersFromDB(manga, editScanlators, dedupe).singleOrNull() ?: emptyList<Chapter>()
+                getChaptersFromDB(manga, editScanlators, dedupe).awaitSingleOrNull() ?: emptyList<Chapter>()
             )
         }
     }
@@ -171,7 +172,7 @@ class MergedSource : SuspendHttpSource() {
             manga = Manga.create(reference.mangaSourceId).apply {
                 url = reference.mangaUrl
             }
-            manga.copyFrom(source.fetchMangaDetails(manga).asFlow().single())
+            manga.copyFrom(source.fetchMangaDetails(manga).awaitSingle())
             try {
                 manga.id = db.insertManga(manga).await().insertedId()
                 reference.mangaId = manga.id
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
index ed809b548..f7d251be0 100755
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/library/LibraryPresenter.kt
@@ -31,10 +31,10 @@ import exh.favorites.FavoritesSyncHelper
 import exh.md.utils.FollowStatus
 import exh.md.utils.MdUtil
 import exh.util.await
+import exh.util.awaitSingleOrNull
 import exh.util.isLewd
 import exh.util.nullIfBlank
 import kotlinx.coroutines.flow.collect
-import kotlinx.coroutines.flow.singleOrNull
 import kotlinx.coroutines.runBlocking
 import rx.Observable
 import rx.Subscription
@@ -502,7 +502,7 @@ class LibraryPresenter(
                     val chapter = db.getChapters(manga).await().minByOrNull { it.source_order }
                     if (chapter != null && !chapter.read) listOf(chapter) else emptyList()
                 } else if (manga.source == MERGED_SOURCE_ID) {
-                    (sourceManager.getOrStub(MERGED_SOURCE_ID) as? MergedSource)?.getChaptersFromDB(manga)?.singleOrNull()?.filter { !it.read } ?: emptyList()
+                    (sourceManager.getOrStub(MERGED_SOURCE_ID) as? MergedSource)?.getChaptersFromDB(manga)?.awaitSingleOrNull()?.filter { !it.read } ?: emptyList()
                 } else /* SY <-- */ db.getChapters(manga).executeAsBlocking()
                     .filter { !it.read }
 
@@ -557,7 +557,7 @@ class LibraryPresenter(
     fun markReadStatus(mangas: List<Manga>, read: Boolean) {
         mangas.forEach { manga ->
             launchIO {
-                val chapters = if (manga.source == MERGED_SOURCE_ID) (sourceManager.get(MERGED_SOURCE_ID) as? MergedSource)?.getChaptersFromDB(manga)?.singleOrNull() ?: emptyList() else db.getChapters(manga).executeAsBlocking()
+                val chapters = if (manga.source == MERGED_SOURCE_ID) (sourceManager.get(MERGED_SOURCE_ID) as? MergedSource)?.getChaptersFromDB(manga)?.awaitSingleOrNull() ?: emptyList() else db.getChapters(manga).executeAsBlocking()
                 chapters.forEach {
                     it.read = read
                     if (!read) {
@@ -646,7 +646,7 @@ class LibraryPresenter(
     // SY -->
     /** Returns first unread chapter of a manga */
     fun getFirstUnread(manga: Manga): Chapter? {
-        val chapters = (if (manga.source == MERGED_SOURCE_ID) (sourceManager.get(MERGED_SOURCE_ID) as? MergedSource).let { runBlocking { it?.getChaptersFromDB(manga)?.singleOrNull() } ?: emptyList() } else db.getChapters(manga).executeAsBlocking())
+        val chapters = (if (manga.source == MERGED_SOURCE_ID) (sourceManager.get(MERGED_SOURCE_ID) as? MergedSource).let { runBlocking { it?.getChaptersFromDB(manga)?.awaitSingleOrNull() } ?: emptyList() } else db.getChapters(manga).executeAsBlocking())
         return if (manga.source == EH_SOURCE_ID || manga.source == EXH_SOURCE_ID) {
             val chapter = chapters.sortedBy { it.source_order }.getOrNull(0)
             if (chapter?.read == false) chapter else null
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt
index 265c79113..9c8ff89b8 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt
@@ -166,7 +166,7 @@ class MangaPresenter(
         // Add the subscription that retrieves the chapters from the database, keeps subscribed to
         // changes, and sends the list of chapters to the relay.
         add(
-            (/* SY --> */if (source is MergedSource) source.getChaptersFromDB(manga, true, dedupe).asObservable() else /* SY <-- */ db.getChapters(manga).asRxObservable())
+            (/* SY --> */if (source is MergedSource) source.getChaptersFromDB(manga, true, dedupe) else /* SY <-- */ db.getChapters(manga).asRxObservable())
                 .map { chapters ->
                     // Convert every chapter to a model.
                     chapters.map { it.toModel() }
diff --git a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt
index 14da640cb..e853bcada 100644
--- a/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt
+++ b/app/src/main/java/eu/kanade/tachiyomi/ui/reader/ReaderPresenter.kt
@@ -35,10 +35,10 @@ import exh.EH_SOURCE_ID
 import exh.EXH_SOURCE_ID
 import exh.MERGED_SOURCE_ID
 import exh.md.utils.FollowStatus
+import exh.util.awaitSingleOrNull
 import exh.util.defaultReaderType
 import exh.util.shouldDeleteChapters
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.singleOrNull
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withContext
 import rx.Completable
@@ -103,7 +103,7 @@ class ReaderPresenter(
      */
     private val chapterList by lazy {
         val manga = manga!!
-        val dbChapters = if (manga.source == MERGED_SOURCE_ID) runBlocking { (sourceManager.get(MERGED_SOURCE_ID) as? MergedSource)?.getChaptersFromDB(manga)?.singleOrNull() ?: emptyList() } else db.getChapters(manga).executeAsBlocking()
+        val dbChapters = if (manga.source == MERGED_SOURCE_ID) runBlocking { (sourceManager.get(MERGED_SOURCE_ID) as? MergedSource)?.getChaptersFromDB(manga)?.awaitSingleOrNull() ?: emptyList() } else db.getChapters(manga).executeAsBlocking()
 
         val selectedChapter = dbChapters.find { it.id == chapterId }
             ?: error("Requested chapter of id $chapterId not found in chapter list")
diff --git a/app/src/main/java/exh/util/RxUtil.kt b/app/src/main/java/exh/util/RxUtil.kt
index 40903211d..b1b37a8fa 100644
--- a/app/src/main/java/exh/util/RxUtil.kt
+++ b/app/src/main/java/exh/util/RxUtil.kt
@@ -158,6 +158,10 @@ suspend fun <T> Observable<T>.awaitLast(): T = last().awaitOne()
 @OptIn(InternalCoroutinesApi::class, ExperimentalCoroutinesApi::class)
 suspend fun <T> Observable<T>.awaitSingle(): T = single().awaitOne()
 
+suspend fun <T> Observable<T>.awaitSingleOrDefault(default: T): T = singleOrDefault(default).awaitOne()
+
+suspend fun <T> Observable<T>.awaitSingleOrNull(): T? = singleOrDefault(null).awaitOne()
+
 @OptIn(InternalCoroutinesApi::class, ExperimentalCoroutinesApi::class)
 private suspend fun <T> Observable<T>.awaitOne(): T = suspendCancellableCoroutine { cont ->
     cont.unsubscribeOnCancellation(