diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d3dfe9b209..488059ad42 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -182,10 +182,11 @@ jobs:
     runs-on: ubuntu-24.04
     needs:
       - common
-    # PR-branch cache saves are invisible to other PRs, so pushes seed the
-    # shared entry test-esp8266-native restores (same pattern as
-    # seed-apt-cache / cache-esp-idf).
-    if: github.event_name == 'push'
+    # PR-branch cache saves are invisible to other PRs, so dev pushes seed
+    # the shared entry test-esp8266-native restores. Only dev: the composite
+    # action saves nowhere else, so a beta/release push would download the
+    # toolchain and discard it.
+    if: github.event_name == 'push' && github.ref == 'refs/heads/dev'
     timeout-minutes: 15
     env:
       # The composite action and the install below agree on this path by
diff --git a/esphome/arduino8266/toolchain.py b/esphome/arduino8266/toolchain.py
index d7d228d74f..988210b949 100644
--- a/esphome/arduino8266/toolchain.py
+++ b/esphome/arduino8266/toolchain.py
@@ -159,9 +159,11 @@ def run_compile(config: ConfigType, verbose: bool) -> int:
             return 1
 
     _print_size_summary(build_dir, paths)
+    from esphome.build_helpers.idedata import IDEDATA_BEST_EFFORT_ERRORS
+
     try:
         idedata = get_idedata(ccache)
-    except (EsphomeError, LookupError, OSError, RuntimeError, ValueError) as err:
+    except IDEDATA_BEST_EFFORT_ERRORS as err:
         # Broad on purpose: idedata is a bonus artifact; nothing here may
         # fail a successful build.
         _LOGGER.warning(
diff --git a/esphome/core/config.py b/esphome/core/config.py
index 472ca64c9a..a0c5022379 100644
--- a/esphome/core/config.py
+++ b/esphome/core/config.py
@@ -564,7 +564,12 @@ NATIVE_ARDUINO_PIO_OPTIONS = frozenset({"board_build.f_cpu", "board_build.ldscri
 # that is stored rather than translated away. Consumed by the esp8266 native
 # backend (later in this chain) for its ignored-option warning; defined here
 # so it stays adjacent to the routing.
-NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS = NATIVE_ARDUINO_PIO_OPTIONS | {"lib_ignore"}
+# build_src_flags: set unconditionally by esp8266/__init__ (throw_stubs) and
+# read by the native generator; not user-routable, so not in the set above
+NATIVE_ARDUINO_CONSUMED_PIO_OPTIONS = NATIVE_ARDUINO_PIO_OPTIONS | {
+    "lib_ignore",
+    "build_src_flags",
+}
 
 
 @coroutine_with_priority(CoroPriority.FINAL)
diff --git a/script/test_build_components.py b/script/test_build_components.py
index e4911ab1d6..01121a277e 100755
--- a/script/test_build_components.py
+++ b/script/test_build_components.py
@@ -1075,13 +1075,26 @@ def test_components(
         )
 
     # Renamed or removed fixtures must shrink coverage loudly, and the
-    # reference-baseline fallback below must not mask an empty match
+    # 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:
+        return any(
+            not platform_filter or test.stem.split(".")[-1].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 p not in all_tests
+            p
+            for p in component_patterns
+            if p and "*" not in p and not _has_platform_test(p)
         ]
     ):
-        print(f"No tests found for requested component(s): {', '.join(unmatched)}")
+        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
diff --git a/tests/script/test_determine_jobs.py b/tests/script/test_determine_jobs.py
index d6bb3f80eb..edd12d8d14 100644
--- a/tests/script/test_determine_jobs.py
+++ b/tests/script/test_determine_jobs.py
@@ -117,6 +117,7 @@ def clear_determine_jobs_caches() -> None:
     """Clear all cached functions before each test."""
     determine_jobs._is_clang_tidy_full_scan.cache_clear()
     determine_jobs._component_has_tests.cache_clear()
+    determine_jobs._cached_components_closure.cache_clear()
 
 
 def test_main_all_tests_should_run(
diff --git a/tests/script/test_test_build_components.py b/tests/script/test_test_build_components.py
index efd4a9e41d..4773d04b6c 100644
--- a/tests/script/test_test_build_components.py
+++ b/tests/script/test_test_build_components.py
@@ -248,13 +248,18 @@ def test_components_empty_match_fails_with_flag(
         ["logger"], "zz-none", "compile", False, fail_on_no_tests=True
     )
     assert rc == 1
-    assert "No tests matched" in capsys.readouterr().out
+    assert "No zz-none tests found" 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."""
-    assert tbc.test_components(["logger"], "zz-none", "compile", False) == 0
+    assert (
+        tbc.test_components(
+            ["logger"], "zz-none", "compile", False, enable_grouping=False
+        )
+        == 0
+    )
 
 
 def test_components_unknown_component_fails_with_flag(
@@ -270,4 +275,7 @@ def test_components_unknown_component_fails_with_flag(
         fail_on_no_tests=True,
     )
     assert rc == 1
-    assert "No tests found for requested component(s)" in capsys.readouterr().out
+    assert (
+        "No esp8266-ard tests found for requested component(s)"
+        in capsys.readouterr().out
+    )
diff --git a/tests/unit_tests/test_arduino8266_toolchain.py b/tests/unit_tests/test_arduino8266_toolchain.py
index 0cf5962559..44916453c9 100644
--- a/tests/unit_tests/test_arduino8266_toolchain.py
+++ b/tests/unit_tests/test_arduino8266_toolchain.py
@@ -500,11 +500,13 @@ def test_print_size_summary_missing_section_skips_summary(
 
 def test_warn_ignored_platformio_options(caplog: pytest.LogCaptureFixture) -> None:
     """Component-added options the native build drops are warned by name;
-    the honored ones (lib_ignore, f_cpu, ldscript) stay quiet."""
+    the honored ones (lib_ignore, f_cpu, ldscript, build_src_flags) stay
+    quiet."""
     CORE.platformio_options = {
         "board_build.ldscript": "eagle.flash.4m2m.ld",
         "board_build.f_cpu": "160000000L",
         "board_build.filesystem": "littlefs",
+        "build_src_flags": "-include throw_stubs.h",
         "lib_ignore": ["Updater"],
         "upload_speed": "460800",
     }
@@ -514,6 +516,7 @@ def test_warn_ignored_platformio_options(caplog: pytest.LogCaptureFixture) -> No
     assert "board_build.ldscript is ignored" not in caplog.text
     assert "board_build.f_cpu is ignored" not in caplog.text
     assert "lib_ignore" not in caplog.text
+    assert "build_src_flags" not in caplog.text
     # Component-added upload_speed never gets read under the native
     # toolchain, so it must warn
     assert "upload_speed" in caplog.text