diff --git a/app/src/main/java/org/thoughtcrime/securesms/logsubmit/SubmitDebugLogActivity.java b/app/src/main/java/org/thoughtcrime/securesms/logsubmit/SubmitDebugLogActivity.java
index 8b46a85b37..aac06c7d90 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/logsubmit/SubmitDebugLogActivity.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/logsubmit/SubmitDebugLogActivity.java
@@ -27,7 +27,7 @@ import androidx.lifecycle.ViewModelProvider;
 
 import com.google.android.material.dialog.MaterialAlertDialogBuilder;
 
-import org.signal.core.util.concurrent.SignalExecutors;
+import org.signal.core.util.ThreadUtil;
 import org.signal.debuglogsviewer.DebugLogsViewer;
 import org.thoughtcrime.securesms.BaseActivity;
 import org.thoughtcrime.securesms.R;
@@ -44,9 +44,9 @@ import org.thoughtcrime.securesms.util.views.CircularProgressMaterialButton;
 import java.util.ArrayList;
 import java.util.List;
 
-import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers;
 import io.reactivex.rxjava3.disposables.CompositeDisposable;
 import io.reactivex.rxjava3.disposables.Disposable;
+import io.reactivex.rxjava3.schedulers.Schedulers;
 
 public class SubmitDebugLogActivity extends BaseActivity {
 
@@ -346,27 +346,29 @@ public class SubmitDebugLogActivity extends BaseActivity {
 
   private void subscribeToLogLines() {
     Disposable disposable = viewModel.getLogLinesObservable()
-        .observeOn(AndroidSchedulers.mainThread())
-        .subscribe(this::presentLines, throwable -> {
+        .observeOn(Schedulers.io())
+        .subscribe(this::appendLines, throwable -> {
           // Handle error
-          this.progressCard.setVisibility(View.GONE);
+          ThreadUtil.runOnMain(() -> {
+            this.progressCard.setVisibility(View.GONE);
+          });
         });
     disposables.add(disposable);
   }
 
-  private void presentLines(@NonNull List<String> lines) {
-    warningBanner.setVisibility(View.VISIBLE);
-    submitButton.setVisibility(View.VISIBLE);
-
-    SignalExecutors.BOUNDED.execute(() -> {
-      StringBuilder lineBuilder = new StringBuilder();
-
-      for (String line : lines) {
-        lineBuilder.append(line).append("\n");
-      }
-
-      DebugLogsViewer.appendLines(logWebView, lineBuilder.toString());
+  private void appendLines(@NonNull List<String> lines) {
+    ThreadUtil.runOnMain(() -> {
+      warningBanner.setVisibility(View.VISIBLE);
+      submitButton.setVisibility(View.VISIBLE);
     });
+
+    StringBuilder lineBuilder = new StringBuilder();
+
+    for (String line : lines) {
+      lineBuilder.append(line).append("\n");
+    }
+
+    DebugLogsViewer.appendLines(logWebView, lineBuilder.toString());
   }
 
   private void presentMode(@NonNull SubmitDebugLogViewModel.Mode mode) {
diff --git a/debuglogs-viewer/lib/src/main/assets/debuglogs-viewer.js b/debuglogs-viewer/lib/src/main/assets/debuglogs-viewer.js
index bfd47ebf01..f7b48a2377 100644
--- a/debuglogs-viewer/lib/src/main/assets/debuglogs-viewer.js
+++ b/debuglogs-viewer/lib/src/main/assets/debuglogs-viewer.js
@@ -220,6 +220,11 @@ function applyFilter() {
   editor.setValue(filtered, -1);
 }
 
+function appendLines(lines) {
+  editor.session.insert({ row: editor.session.getLength(), column: 0}, lines);
+  logLines += lines;
+}
+
 function readLines(offset, limit) {
   const lines = logLines.split("\n")
   if (offset >= lines.length) {
diff --git a/debuglogs-viewer/lib/src/main/java/org/signal/debuglogsviewer/DebugLogsViewer.kt b/debuglogs-viewer/lib/src/main/java/org/signal/debuglogsviewer/DebugLogsViewer.kt
index 29f842c744..44f39e9433 100644
--- a/debuglogs-viewer/lib/src/main/java/org/signal/debuglogsviewer/DebugLogsViewer.kt
+++ b/debuglogs-viewer/lib/src/main/java/org/signal/debuglogsviewer/DebugLogsViewer.kt
@@ -46,7 +46,11 @@ object DebugLogsViewer {
   fun appendLines(webview: WebView, lines: String) {
     // Set the debug log lines
     val escaped = JSONObject.quote(lines)
-    ThreadUtil.runOnMain { webview.evaluateJavascript("editor.insert($escaped); logLines+=$escaped;", null) }
+    val latch = CountDownLatch(1)
+    ThreadUtil.runOnMain {
+      webview.evaluateJavascript("appendLines($escaped)") { latch.countDown() }
+    }
+    latch.await()
   }
 
   @JvmStatic