diff --git a/CHANGELOG.md b/CHANGELOG.md
index d03f979e..fe84e8ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+0.5.1
+=====
+- OSUpdate app: pause download when wifi is lost, resume when reconnected
+- Fri3d Camp 2024 Badge: workaround ADC2+WiFi conflict by disconnecting WiFi to measure battery level
+
 0.5.0
 =====
 - ESP32: one build to rule them all; instead of 2 builds per supported board, there is now one single build that identifies and initializes the board at runtime!
diff --git a/internal_filesystem/builtin/apps/com.micropythonos.osupdate/assets/osupdate.py b/internal_filesystem/builtin/apps/com.micropythonos.osupdate/assets/osupdate.py
index 15f2cc52..3af8c3d8 100644
--- a/internal_filesystem/builtin/apps/com.micropythonos.osupdate/assets/osupdate.py
+++ b/internal_filesystem/builtin/apps/com.micropythonos.osupdate/assets/osupdate.py
@@ -576,9 +576,13 @@ class UpdateDownloader:
             if self._is_network_error(e):
                 print(f"UpdateDownloader: Network error ({e}), pausing download")
                 self.is_paused = True
-                self.bytes_written_so_far = result.get('bytes_written', self.bytes_written_so_far)
+                # Only update bytes_written_so_far if we actually wrote bytes in this attempt
+                # Otherwise preserve the existing state (important for resume failures)
+                if result.get('bytes_written', 0) > 0:
+                    self.bytes_written_so_far = result['bytes_written']
                 result['paused'] = True
                 result['bytes_written'] = self.bytes_written_so_far
+                result['total_size'] = self.total_size_expected  # Preserve total size for UI
             else:
                 # Non-network error
                 result['error'] = str(e)
diff --git a/tests/test_osupdate.py b/tests/test_osupdate.py
index e5a888ba..16e52fd2 100644
--- a/tests/test_osupdate.py
+++ b/tests/test_osupdate.py
@@ -460,4 +460,27 @@ class TestUpdateDownloader(unittest.TestCase):
         self.assertIn('Range', last_request['headers'])
         self.assertEqual(last_request['headers']['Range'], 'bytes=8192-')
 
+    def test_resume_failure_preserves_state(self):
+        """Test that resume failures preserve download state for retry."""
+        # Simulate partial download state
+        self.downloader.bytes_written_so_far = 245760  # 60 chunks already downloaded
+        self.downloader.total_size_expected = 3391488
+
+        # Resume attempt fails immediately with EHOSTUNREACH (network not ready)
+        self.mock_requests.set_exception(OSError(-118, "EHOSTUNREACH"))
+
+        result = self.downloader.download_and_install(
+            "http://example.com/update.bin"
+        )
+
+        # Should pause, not fail
+        self.assertFalse(result['success'])
+        self.assertTrue(result['paused'])
+        self.assertIsNone(result['error'])
+
+        # Critical: Must preserve progress for next retry
+        self.assertEqual(result['bytes_written'], 245760, "Must preserve bytes_written")
+        self.assertEqual(result['total_size'], 3391488, "Must preserve total_size")
+        self.assertEqual(self.downloader.bytes_written_so_far, 245760, "Must preserve internal state")
+