diff --git a/.github/actions/cache-arduino8266/action.yml b/.github/actions/cache-arduino8266/action.yml
index b23db96769..affe62b5aa 100644
--- a/.github/actions/cache-arduino8266/action.yml
+++ b/.github/actions/cache-arduino8266/action.yml
@@ -17,9 +17,9 @@ runs:
       id: version
       shell: bash
       run: |
-        # One owner for the install prefix: exporting it here (instead of a
-        # per-job env stanza) makes it impossible for a caller to install
-        # into a path other than the one cached below.
+        # One owner for the install prefix: exported here and referenced by
+        # the cache steps below via env, so the caller's install and the
+        # cached path cannot diverge.
         echo "ESPHOME_ARDUINO8266_PREFIX=$HOME/.esphome-arduino8266" >> "$GITHUB_ENV"
         . venv/bin/activate
         key=$(python -c 'from esphome.components.esp8266 import RECOMMENDED_ARDUINO_FRAMEWORK_VERSION as f; from esphome.arduino8266.framework import TOOLCHAIN_VERSION as t; print(f"{f}-{t}")')
@@ -29,11 +29,11 @@ runs:
       if: github.ref == 'refs/heads/dev'
       uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
       with:
-        path: ~/.esphome-arduino8266
+        path: ${{ env.ESPHOME_ARDUINO8266_PREFIX }}
         key: ${{ runner.os }}-esp8266-native-${{ steps.version.outputs.key }}
     - name: Restore the native toolchain (off dev)
       if: github.ref != 'refs/heads/dev'
       uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
       with:
-        path: ~/.esphome-arduino8266
+        path: ${{ env.ESPHOME_ARDUINO8266_PREFIX }}
         key: ${{ runner.os }}-esp8266-native-${{ steps.version.outputs.key }}
diff --git a/esphome/arduino8266/toolchain.py b/esphome/arduino8266/toolchain.py
index dec3e7caf7..0d7fe51622 100644
--- a/esphome/arduino8266/toolchain.py
+++ b/esphome/arduino8266/toolchain.py
@@ -116,6 +116,11 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
         cmd.append("-v")
     if jobs := config[CONF_ESPHOME].get(CONF_COMPILE_PROCESS_LIMIT):
         cmd += ["-j", str(jobs)]
+    # Explicit targets, not the default statement: a generator defect that
+    # drops them fails loudly with "unknown target" instead of a green
+    # no-op run that leaves stale artifacts in place
+    targets = ["firmware.factory.bin", "firmware.ota.bin"]
+    cmd += targets
 
     # A dry-run probe keeps a no-op rebuild quiet: ninja would only print
     # "no work to do". A freshly rewritten manifest all but guarantees work,
@@ -124,7 +129,7 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
     skip_build = False
     if not ninja_changed:
         probe = subprocess.run(
-            [str(paths.ninja), "-n"],
+            [str(paths.ninja), "-n", *targets],
             cwd=build_dir,
             env=env,
             capture_output=True,
@@ -137,6 +142,10 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
             # flags a generator bug; the skip branch would otherwise
             # swallow it forever
             _LOGGER.warning("ninja: %s", probe.stderr.strip())
+        if probe.returncode != 0:
+            # An unknown target here is the defective-manifest case; fall
+            # through to the real build so the error prints attributably
+            _LOGGER.debug("ninja probe failed; running the full build")
         skip_build = probe.returncode == 0 and "no work to do" in probe.stdout
     if skip_build:
         _LOGGER.debug("ninja: nothing to rebuild")
@@ -148,29 +157,19 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
         if rc != 0:
             return rc
 
-    # A generator defect emitting no default targets must not turn into a
-    # green build with no firmware (size summary and idedata only warn);
-    # the factory/ota copies are what upload and OTA actually consume
+    # ninja already refused a manifest missing the explicit targets above;
+    # existence covers the remaining hole (a rule that ran but wrote
+    # elsewhere). The factory/ota copies are what upload and OTA consume.
     build_dir_artifacts = (
         get_elf_path(),
         build_dir / "firmware.bin",
         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
diff --git a/esphome/components/esp8266/__init__.py b/esphome/components/esp8266/__init__.py
index 97b9ad8acd..7422bcd9b2 100644
--- a/esphome/components/esp8266/__init__.py
+++ b/esphome/components/esp8266/__init__.py
@@ -682,7 +682,9 @@ def _decode_pc(config: ConfigType, addr: str) -> None:
         return
 
     if "?? ??:0" in translation:
-        # Nothing useful
+        # A stale or mismatched ELF: mark it, or the frame silently reads
+        # as merely unmappable
+        _LOGGER.warning("Not decoded %s (address not in %s)", addr, elf)
         return
     translation = translation.replace(" at ??:?", "").replace(":?", "")
     _LOGGER.warning("Decoded %s", translation)
diff --git a/esphome/writer.py b/esphome/writer.py
index 37114f84e5..435c4804f1 100644
--- a/esphome/writer.py
+++ b/esphome/writer.py
@@ -612,12 +612,15 @@ def clean_build(clear_pio_cache: bool = True, *, full: bool = False):
 
     # The idedata caches are derived from the build but live under the data
     # dir, not the build path, so they must be removed separately in both
-    # modes (the .arduino.json variant is the native esp8266 toolchain's).
-    for cache_name in (f"{CORE.name}.json", f"{CORE.name}.arduino.json"):
-        idedata_cache = CORE.relative_internal_path("idedata", cache_name)
-        if idedata_cache.is_file():
-            _LOGGER.info("Deleting %s", idedata_cache)
-            idedata_cache.unlink()
+    # modes. Globbed (name.json plus name.<backend>.json) so a future
+    # backend suffix cannot silently drift out of clean-all.
+    idedata_dir = CORE.relative_internal_path("idedata")
+    for idedata_cache in (
+        *idedata_dir.glob(f"{CORE.name}.json"),
+        *idedata_dir.glob(f"{CORE.name}.*.json"),
+    ):
+        _LOGGER.info("Deleting %s", idedata_cache)
+        idedata_cache.unlink()
 
     if not clear_pio_cache:
         return
diff --git a/script/test_build_components.py b/script/test_build_components.py
index 28026d5775..d50e9f5847 100755
--- a/script/test_build_components.py
+++ b/script/test_build_components.py
@@ -1062,17 +1062,19 @@ def test_components(
     # toolchain build.
     include_validate = esphome_command != "compile"
 
-    # Find all component tests
+    # Find all component tests; remember which patterns (wildcards
+    # included) matched anything, for the deferred no-tests accounting
     all_tests = {}
+    pattern_hits: dict[str, bool] = {}
     for pattern in component_patterns:
         # Skip empty patterns (happens when components list is empty string)
         if not pattern:
             continue
-        all_tests.update(
-            find_component_tests(
-                tests_dir, pattern, base_only, include_validate=include_validate
-            )
+        found = find_component_tests(
+            tests_dir, pattern, base_only, include_validate=include_validate
         )
+        pattern_hits[pattern] = bool(found)
+        all_tests.update(found)
 
     # The flag's contract is "no test matched fails": a fully blank pattern
     # list would otherwise slide into the reference-baseline fallback and
@@ -1081,39 +1083,6 @@ def test_components(
         print("No components requested (blank component list)")
         return 1
 
-    # Renamed or removed fixtures must shrink coverage loudly, and the
-    # reference-baseline fallback below must not mask an empty match. The
-    # check is per platform: a component whose fixture exists only for other
-    # platforms contributes nothing to this leg.
-    def _has_platform_test(component: str) -> bool:
-        # "all" fixtures build on every platform (mirrors the run loop)
-        return any(
-            not platform_filter
-            or (suffix := test.stem.split(".")[-1]) == "all"
-            or suffix.startswith(platform_filter)
-            for test in all_tests.get(component, [])
-        )
-
-    if fail_on_no_tests and (
-        unmatched := [
-            p
-            for p in component_patterns
-            if p and "*" not in p and not _has_platform_test(p)
-        ]
-    ):
-        target = f"{platform_filter} " if platform_filter else ""
-        print(
-            f"No {target}tests found for requested component(s): {', '.join(unmatched)}"
-        )
-        return 1
-
-    # 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(
@@ -1219,21 +1188,21 @@ def test_components(
 
     silent: list[str] = []
     if fail_on_no_tests:
-        # A green run that built nothing for a requested component (renamed
-        # fixture, missing base file, version-suffix mismatch) must not pass
-        # CI. Per component: an all-or-nothing check would let one silent
-        # component hide behind the others. Opt-in: some legs (the esp32-ard
-        # smoke subset) legitimately match nothing. Failing is deferred past
-        # the summary so a real failure's reproduce commands still print.
+        # A green run that built nothing for a requested pattern (renamed
+        # fixture, missing base file, version-suffix mismatch, a wildcard
+        # matching no component) must not pass CI. Per pattern: an
+        # all-or-nothing check would let one silent pattern hide behind the
+        # others. Opt-in: some legs (the esp32-ard smoke subset)
+        # legitimately match nothing. Failing is deferred past the summary
+        # so a real failure's reproduce commands still print.
         built = {c for r in test_results for c in r.components}
         silent = [
-            p for p in component_patterns if p and "*" not in p and p not in built
+            p
+            for p in component_patterns
+            if p and (not pattern_hits.get(p) or ("*" not in p and p not in built))
         ]
         if silent:
-            print(f"No tests ran for requested component(s): {', '.join(silent)}")
-        elif not test_results:
-            print("No tests matched the requested components/platform")
-            return 1
+            print(f"No tests ran for requested pattern(s): {', '.join(silent)}")
 
     # Separate results into passed and failed
     passed_results = [r for r in test_results if r.success]
diff --git a/tests/script/test_test_build_components.py b/tests/script/test_test_build_components.py
index 3f19935e0b..214c1e1273 100644
--- a/tests/script/test_test_build_components.py
+++ b/tests/script/test_test_build_components.py
@@ -245,10 +245,15 @@ def test_components_empty_match_fails_with_flag(
     with no matching test file must not pass CI as a green zero-component
     compile."""
     rc = tbc.test_components(
-        ["logger"], "zz-none", "compile", False, fail_on_no_tests=True
+        ["logger"],
+        "zz-none",
+        "compile",
+        False,
+        enable_grouping=False,
+        fail_on_no_tests=True,
     )
     assert rc == 1
-    assert "No zz-none tests found" in capsys.readouterr().out
+    assert "No tests ran for requested pattern(s): logger" in (capsys.readouterr().out)
 
 
 def test_components_component_with_no_base_file_fails_with_flag(
@@ -268,9 +273,7 @@ def test_components_component_with_no_base_file_fails_with_flag(
         fail_on_no_tests=True,
     )
     assert rc == 1
-    assert "No tests ran for requested component(s): logger" in (
-        capsys.readouterr().out
-    )
+    assert "No tests ran for requested pattern(s): logger" in (capsys.readouterr().out)
 
 
 def test_components_blank_list_fails_with_flag(
@@ -291,10 +294,17 @@ def test_components_wildcard_no_match_fails_with_flag(
     """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
+        ["zz_no_such*"],
+        "esp8266-ard",
+        "compile",
+        False,
+        enable_grouping=False,
+        fail_on_no_tests=True,
     )
     assert rc == 1
-    assert "No components found matching" in capsys.readouterr().out
+    assert "No tests ran for requested pattern(s): zz_no_such*" in (
+        capsys.readouterr().out
+    )
 
 
 def test_components_empty_match_tolerated_without_flag() -> None:
@@ -318,10 +328,10 @@ def test_components_unknown_component_fails_with_flag(
         "esp8266-ard",
         "compile",
         False,
+        enable_grouping=False,
         fail_on_no_tests=True,
     )
     assert rc == 1
-    assert (
-        "No esp8266-ard tests found for requested component(s)"
-        in capsys.readouterr().out
+    assert "No tests ran for requested pattern(s): no_such_component_xyz" in (
+        capsys.readouterr().out
     )
diff --git a/tests/unit_tests/test_arduino8266_toolchain.py b/tests/unit_tests/test_arduino8266_toolchain.py
index a5c4df6c14..4ceeba670b 100644
--- a/tests/unit_tests/test_arduino8266_toolchain.py
+++ b/tests/unit_tests/test_arduino8266_toolchain.py
@@ -53,18 +53,6 @@ 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",
@@ -122,9 +110,11 @@ def test_run_compile_success(tmp_path: Path) -> None:
     assert rc == 0
     # The -n probe runs first, then the real build (cwd, no -C banner)
     ninja_calls = [c for c in mock_run.call_args_list if "ninja" in str(c[0][0][0])]
-    assert ninja_calls[0][0][0][-1] == "-n"
+    assert "-n" in ninja_calls[0][0][0]
+    # Explicit targets: a manifest missing them fails as "unknown target"
+    assert ninja_calls[0][0][0][-1] == "firmware.ota.bin"
     cmd = ninja_calls[1][0][0]
-    assert cmd[-2:] == ["-j", "4"]
+    assert cmd[-4:] == ["-j", "4", "firmware.factory.bin", "firmware.ota.bin"]
     assert "-C" not in cmd
     assert ninja_calls[1][1]["cwd"] is not None
     mock_compdb.assert_called_once()
@@ -155,7 +145,9 @@ def test_run_compile_noop_skips_the_build_spawn(tmp_path: Path) -> None:
     assert rc == 0
     ninja_calls = [c for c in mock_run.call_args_list if "ninja" in str(c[0][0][0])]
     assert len(ninja_calls) == 1
-    assert ninja_calls[0][0][0][-1] == "-n"
+    assert "-n" in ninja_calls[0][0][0]
+    # Explicit targets: a manifest missing them fails as "unknown target"
+    assert ninja_calls[0][0][0][-1] == "firmware.ota.bin"
 
 
 def test_run_compile_regenerates_stale_compdb(tmp_path: Path) -> None:
@@ -164,7 +156,6 @@ 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)
@@ -437,7 +428,6 @@ 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 (
@@ -587,31 +577,6 @@ 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: