diff --git a/esphome/arduino8266/toolchain.py b/esphome/arduino8266/toolchain.py
index ad7134cb8a..d73e9aad4e 100644
--- a/esphome/arduino8266/toolchain.py
+++ b/esphome/arduino8266/toolchain.py
@@ -151,10 +151,20 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
         get_factory_firmware_path(),
         build_dir / "firmware.ota.bin",
     )
+    ninja_mtime = ninja_file.stat().st_mtime
     for artifact in build_dir_artifacts:
         if not artifact.is_file():
             _LOGGER.error("Build produced no %s", artifact)
             return 1
+        if artifact.stat().st_mtime < ninja_mtime:
+            # A leftover from an older manifest must not pass as this
+            # build's output (a defective manifest with no default targets
+            # reports "no work to do" while building nothing)
+            _LOGGER.error(
+                "%s is older than build.ninja; run 'esphome clean-all' and retry",
+                artifact,
+            )
+            return 1
 
     if not _print_size_summary(build_dir, paths):
         # The cause was already warned; name the consequence so a build
@@ -214,7 +224,9 @@ def _parse_app_size(build_dir: Path, paths: framework.InstalledPaths) -> int | N
     ld_path = get_flash_ld_path(build_dir, paths)
     try:
         ld_text = ld_path.read_text(encoding="utf-8")
-    except OSError as err:
+    except (OSError, UnicodeDecodeError) as err:
+        # UnicodeDecodeError: a truncated/corrupt script must degrade to
+        # the same warning, never abort an already-linked build
         _LOGGER.warning("Cannot read linker script for the Flash summary: %s", err)
         return None
     app_size = segment_length(ld_text, "irom0_0_seg")
diff --git a/esphome/components/esp8266/__init__.py b/esphome/components/esp8266/__init__.py
index 52e48925f2..b5852abc46 100644
--- a/esphome/components/esp8266/__init__.py
+++ b/esphome/components/esp8266/__init__.py
@@ -664,10 +664,13 @@ def _decode_pc(config: ConfigType, addr: str) -> None:
     try:
         translation = subprocess.check_output(command, close_fds=False).decode().strip()
     except Exception as err:  # noqa: BLE001  # pylint: disable=broad-except
-        # Warn, not debug: a failing addr2line must be visible
+        # Warn, not debug: a failing addr2line must be visible. The warning
+        # is rate-limited across a dump, so mark every undecoded address
+        # inline or the rest read as merely unmappable
         _warn_decode_problem(
             "addr2line-failed", "Could not decode crash address %s (%s)", addr, err
         )
+        _LOGGER.warning("Not decoded %s (addr2line failed)", addr)
         _LOGGER.debug("Caught exception for command %s", command, exc_info=1)
         return
 
diff --git a/script/test_build_components.py b/script/test_build_components.py
index 26c49cf60f..06a2ea09f5 100755
--- a/script/test_build_components.py
+++ b/script/test_build_components.py
@@ -1106,6 +1106,11 @@ def test_components(
 
     # If no components found, build a reference configuration for baseline comparison
     # Create a synthetic "empty" component test that will build just the base config
+    if fail_on_no_tests and not all_tests:
+        # The synthetic baseline would report success having built nothing
+        # the caller asked for (e.g. a wildcard that matched no component)
+        print(f"No components found matching: {component_patterns}")
+        return 1
     if not all_tests:
         print(f"No components found matching: {component_patterns}")
         print(
diff --git a/tests/script/test_test_build_components.py b/tests/script/test_test_build_components.py
index a293ebcb16..3f19935e0b 100644
--- a/tests/script/test_test_build_components.py
+++ b/tests/script/test_test_build_components.py
@@ -285,6 +285,18 @@ def test_components_blank_list_fails_with_flag(
     assert "blank component list" in capsys.readouterr().out
 
 
+def test_components_wildcard_no_match_fails_with_flag(
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    """A wildcard matching nothing must not degrade to the synthetic
+    baseline build and exit green under the flag."""
+    rc = tbc.test_components(
+        ["zz_no_such*"], "esp8266-ard", "compile", False, fail_on_no_tests=True
+    )
+    assert rc == 1
+    assert "No components found matching" in capsys.readouterr().out
+
+
 def test_components_empty_match_tolerated_without_flag() -> None:
     """The esp32-ard smoke leg deliberately builds only the subset with a
     matching fixture; without the flag an empty match stays green."""
diff --git a/tests/unit_tests/test_arduino8266_toolchain.py b/tests/unit_tests/test_arduino8266_toolchain.py
index 82f950e7fa..a5c4df6c14 100644
--- a/tests/unit_tests/test_arduino8266_toolchain.py
+++ b/tests/unit_tests/test_arduino8266_toolchain.py
@@ -39,9 +39,11 @@ def _setup_core(tmp_path: Path) -> None:
     CORE.build_path = tmp_path
     CORE.data[KEY_CORE] = {KEY_FRAMEWORK_VERSION: cv.Version(3, 1, 2)}
     # run_compile verifies the produced artifacts; give every test a build
-    # that "produced" them (tests for the guard delete them again)
+    # that "produced" them (tests for the guard delete them again). The
+    # manifest comes first: artifacts must not be older than build.ninja.
     build_dir = CORE.relative_pioenvs_path("test8266")
     build_dir.mkdir(parents=True, exist_ok=True)
+    (build_dir / "build.ninja").write_text("# manifest")
     for artifact in (
         "firmware.elf",
         "firmware.bin",
@@ -51,6 +53,18 @@ def _setup_core(tmp_path: Path) -> None:
         (build_dir / artifact).write_bytes(b"")
 
 
+def _touch_artifacts(build_dir: Path) -> None:
+    """Re-date the fixture artifacts after a test rewrites build.ninja, so
+    the freshness guard sees them as this manifest's outputs."""
+    for artifact in (
+        "firmware.elf",
+        "firmware.bin",
+        "firmware.factory.bin",
+        "firmware.ota.bin",
+    ):
+        (build_dir / artifact).touch()
+
+
 def _paths(tmp_path: Path) -> framework.InstalledPaths:
     return framework.InstalledPaths(
         framework=tmp_path / "framework",
@@ -150,6 +164,7 @@ def test_run_compile_regenerates_stale_compdb(tmp_path: Path) -> None:
     build_dir = toolchain.get_build_dir()
     build_dir.mkdir(parents=True, exist_ok=True)
     (build_dir / "build.ninja").write_text("")
+    _touch_artifacts(build_dir)
     compdb = build_dir / "compile_commands.json"
     compdb.write_text("[]")
     os.utime(compdb, ((build_dir / "build.ninja").stat().st_mtime - 5,) * 2)
@@ -422,6 +437,7 @@ def test_run_compile_skips_compdb_when_ninja_unchanged(tmp_path: Path) -> None:
     build_dir.mkdir(parents=True, exist_ok=True)
     # write_project (stubbed below) always leaves a build.ninja behind
     (build_dir / "build.ninja").write_text("# manifest")
+    _touch_artifacts(build_dir)
 
     def run(regenerate_expected: bool) -> None:
         with (
@@ -571,6 +587,44 @@ def test_run_compile_skipped_size_summary_names_consequence(
     assert "Firmware size summary unavailable for this build" in caplog.text
 
 
+def test_run_compile_stale_artifact_fails(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """An artifact older than build.ninja is a leftover, not this build's
+    output; a defective manifest with no default targets must not pass on
+    it."""
+    build_dir = toolchain.get_build_dir()
+    os.utime(build_dir / "firmware.bin", (0, 0))
+    with (
+        patch.object(framework, "check_and_install", return_value=_paths(tmp_path)),
+        patch.object(framework, "get_build_env", return_value={}),
+        patch("esphome.build_gen.arduino8266.write_project", return_value=False),
+        patch.object(
+            toolchain.subprocess,
+            "run",
+            return_value=MagicMock(returncode=0, stdout="", stderr=""),
+        ),
+        patch.object(toolchain, "_write_compile_commands"),
+        patch.object(toolchain, "_print_size_summary", return_value=True),
+        patch.object(toolchain, "get_idedata", return_value={}),
+    ):
+        assert toolchain.run_compile({CONF_ESPHOME: {}}, verbose=False) == 1
+    assert "older than build.ninja" in caplog.text
+
+
+def test_parse_app_size_non_utf8_ld_warns(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    """A corrupt (non-UTF-8) linker script degrades to the same warning as
+    an unreadable one, never a traceback after a successful link."""
+    paths = _paths(tmp_path)
+    ld = tmp_path / "corrupt.ld"
+    ld.write_bytes(b"\xff\xfe not utf8")
+    with patch("esphome.build_gen.arduino8266.get_flash_ld_path", return_value=ld):
+        assert toolchain._parse_app_size(tmp_path, paths) is None
+    assert "Cannot read linker script" in caplog.text
+
+
 def test_get_idedata_accepts_preresolved_ccache() -> None:
     """run_compile threads its resolved ccache through; the probe must not
     run again."""