diff --git a/src/mvt/android/artifacts/tombstone_crashes.py b/src/mvt/android/artifacts/tombstone_crashes.py
index bcfb389..1b6e115 100644
--- a/src/mvt/android/artifacts/tombstone_crashes.py
+++ b/src/mvt/android/artifacts/tombstone_crashes.py
@@ -191,9 +191,14 @@ class TombstoneCrashArtifact(AndroidArtifact):
     def _load_key_value_line(
         self, line: str, key: str, destination_key: str, tombstone: dict
     ) -> bool:
-        line_key, value = line.split(":", 1)
-        if line_key != key:
-            raise ValueError(f"Expected key {key}, got {line_key}")
+        # The caller matched the key as a bare prefix, so a longer word starting
+        # with it arrives here: `Caused by: …` inside an abort message reaches
+        # the `Cause` key. That is a different line, not a broken file — say so
+        # by declining it, and let the remaining keys have their turn. Raising
+        # here discarded the whole tombstone, crash and stack trace included.
+        line_key, separator, value = line.partition(":")
+        if not separator or line_key != key:
+            return False
 
         value_clean = value.strip().strip("'")
         if destination_key == "uid":
diff --git a/src/mvt/android/cmd_check_androidqf.py b/src/mvt/android/cmd_check_androidqf.py
index ffa3e13..99ac5a3 100644
--- a/src/mvt/android/cmd_check_androidqf.py
+++ b/src/mvt/android/cmd_check_androidqf.py
@@ -292,9 +292,7 @@ class CmdAndroidCheckAndroidQF(Command):
         try:
             cmd.from_ab(backup)
         except InvalidAndroidBackup as exc:
-            self.log.warning(
-                "Skipping backup modules as backup.ab is malformed: %s", exc
-            )
+            self.log.warning("Skipping backup modules: %s", exc)
             return False
 
         cmd.run()
diff --git a/src/mvt/android/cmd_check_backup.py b/src/mvt/android/cmd_check_backup.py
index b75bb34..94be4ee 100644
--- a/src/mvt/android/cmd_check_backup.py
+++ b/src/mvt/android/cmd_check_backup.py
@@ -87,11 +87,15 @@ class CmdAndroidCheckBackup(Command):
         if header["encryption"] != "none":
             password = prompt_or_load_android_backup_password(log, self.module_options)
             if not password:
+                if self.sub_command:
+                    raise InvalidAndroidBackup("No backup password provided")
                 log.critical("No backup password provided.")
                 sys.exit(1)
         try:
             tardata = parse_backup_file(ab_file_bytes, password=password)
         except InvalidBackupPassword:
+            if self.sub_command:
+                raise InvalidAndroidBackup("Invalid backup password")
             log.critical("Invalid backup password")
             sys.exit(1)
         except AndroidBackupParsingError as exc:
diff --git a/tests/android/test_artifact_tombstone_caused_by.py b/tests/android/test_artifact_tombstone_caused_by.py
new file mode 100644
index 0000000..9a2df85
--- /dev/null
+++ b/tests/android/test_artifact_tombstone_caused_by.py
@@ -0,0 +1,54 @@
+# Mobile Verification Toolkit (MVT)
+# Copyright (c) 2021-2023 The MVT Authors.
+# Use of this software is governed by the MVT License 1.1 that can be found at
+#   https://license.mvt.re/1.1/
+"""A `Caused by:` line must not discard the whole text tombstone.
+
+Keys are matched as bare prefixes, so `Caused by: …` — an ordinary line inside
+an abort message — reached the `Cause` key, failed the key comparison and
+raised, which `Tombstones.run()` logged while dropping the entire crash record.
+Seen on a 1.6 MB tombstone whose protobuf twin was zero bytes: the crash then
+had no representation at all.
+"""
+
+import datetime
+
+from mvt.android.artifacts.tombstone_crashes import TombstoneCrashArtifact
+
+TOMBSTONE = b"""\
+*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
+Build fingerprint: 'Xiaomi/vili_eea/vili:13/TKQ1.220829.002/V14.0.10.0:user/release-keys'
+Revision: '0'
+ABI: 'arm64'
+Timestamp: 2023-08-24 14:54:47.999124034+0300
+Process uptime: 12199s
+Cmdline: com.example.game
+pid: 8044, tid: 26222, name: UnityMain  >>> com.example.game <<<
+uid: 10235
+signal 6 (SIGABRT), code -1 (SI_QUEUE), fault addr --------
+Abort message: 'No pending exception expected: java.lang.SecurityException: listen
+  at void android.os.Parcel.readException() (Parcel.java:2920)
+Caused by: android.os.RemoteException: Remote stack trace:
+\tat com.android.server.TelephonyRegistry.listen(TelephonyRegistry.java:1096)
+"""
+
+WITH_CAUSE = TOMBSTONE + b"Cause: null pointer dereference\n"
+
+
+class TestTombstoneCausedBy:
+    def _parse(self, content):
+        artifact = TombstoneCrashArtifact()
+        artifact.results = []
+        artifact.parse("tombstone_23", datetime.datetime(2023, 8, 24), content)
+        return artifact.results
+
+    def test_caused_by_line_does_not_discard_the_tombstone(self):
+        results = self._parse(TOMBSTONE)
+        assert len(results) == 1
+        assert results[0]["pid"] == 8044
+        assert results[0]["process_name"] == "UnityMain"
+        assert results[0]["uid"] == 10235
+
+    def test_the_real_cause_key_is_still_parsed(self):
+        results = self._parse(WITH_CAUSE)
+        assert results[0]["cause"] == "null pointer dereference"
diff --git a/tests/android/test_check_backup_optional_failure.py b/tests/android/test_check_backup_optional_failure.py
new file mode 100644
index 0000000..72dae42
--- /dev/null
+++ b/tests/android/test_check_backup_optional_failure.py
@@ -0,0 +1,39 @@
+# Mobile Verification Toolkit (MVT)
+# Copyright (c) 2021-2023 The MVT Authors.
+# Use of this software is governed by the MVT License 1.1 that can be found at
+#   https://license.mvt.re/1.1/
+"""An encrypted backup.ab must not take the whole check-androidqf run with it.
+
+`CmdAndroidCheckBackup.from_ab()` already raises `InvalidAndroidBackup` instead
+of exiting when it runs as a sub-command (`check-androidqf` catches that and
+skips the backup modules), for a wrong file format and for a parse error. The
+password branches used to call `sys.exit(1)` unconditionally, which ends the
+parent run inside `finish()` — before the intrusion-logs command and before the
+timeline, alerts, urls, info and run-manifest are written.
+"""
+
+import pytest
+
+from mvt.android.cmd_check_backup import CmdAndroidCheckBackup, InvalidAndroidBackup
+
+ENCRYPTED_AB_HEADER = b"ANDROID BACKUP\n5\n0\nAES-256\n" + b"\x00" * 64
+
+
+class TestCheckBackupOptionalFailure:
+    def _cmd(self, tmp_path, sub_command):
+        return CmdAndroidCheckBackup(
+            target_path=None,
+            results_path=str(tmp_path),
+            module_options={"interactive": False},
+            sub_command=sub_command,
+        )
+
+    def test_missing_password_raises_when_nested(self, tmp_path):
+        cmd = self._cmd(tmp_path, sub_command=True)
+        with pytest.raises(InvalidAndroidBackup):
+            cmd.from_ab(ENCRYPTED_AB_HEADER)
+
+    def test_missing_password_still_exits_on_its_own_command(self, tmp_path):
+        cmd = self._cmd(tmp_path, sub_command=False)
+        with pytest.raises(SystemExit):
+            cmd.from_ab(ENCRYPTED_AB_HEADER)
diff --git a/tests/test_check_android_androidqf.py b/tests/test_check_android_androidqf.py
index 2253a50..4e6ef98 100644
--- a/tests/test_check_android_androidqf.py
+++ b/tests/test_check_android_androidqf.py
@@ -155,7 +155,7 @@ class TestCheckAndroidqfCommand:
             result = runner.invoke(check_androidqf, [str(path)])
 
         assert result.exit_code == 0
-        assert "Skipping backup modules as backup.ab is malformed" in caplog.text
+        assert "Skipping backup modules: Invalid backup format" in caplog.text
         assert not any(
             record.levelname in {"CRITICAL", "FATAL"} for record in caplog.records
         )