diff --git a/esphome/arduino8266/component.py b/esphome/arduino8266/component.py
index 50c5a5f76d..111e407dbc 100644
--- a/esphome/arduino8266/component.py
+++ b/esphome/arduino8266/component.py
@@ -90,7 +90,16 @@ def _library_info(name: str, read_path: Path, data: dict) -> ArduinoLibrary:
         if tok.startswith("-I"):
             include_flags.append(tok[2:])
         elif tok.startswith("-L"):
-            lib.link_dirs.append((read_path / tok[2:]).resolve())
+            link_dir = (read_path / tok[2:]).resolve()
+            if not link_dir.is_dir():
+                # Kept anyway (the linker ignores missing -L dirs); the
+                # warning names the culprit before a bare "cannot find -lfoo"
+                _LOGGER.warning(
+                    "Library %s declares library dir %s which does not exist",
+                    name,
+                    tok[2:],
+                )
+            lib.link_dirs.append(link_dir)
         elif tok.startswith("-l"):
             lib.link_libs.append(tok[2:])
         elif tok.startswith("-Wl,"):
diff --git a/esphome/build_gen/arduino8266.py b/esphome/build_gen/arduino8266.py
index 80c0730aa0..112f90172a 100644
--- a/esphome/build_gen/arduino8266.py
+++ b/esphome/build_gen/arduino8266.py
@@ -15,6 +15,7 @@ from the build flags with the same precedence as the PlatformIO builder.
 from __future__ import annotations
 
 from dataclasses import dataclass, field
+import logging
 import os
 from pathlib import Path
 import re
@@ -41,6 +42,8 @@ from esphome.framework_helpers import get_project_cxx_compile_flags
 from esphome.helpers import mkdir_p, write_file_if_changed
 from esphome.platformio.library import join_flag_args
 
+_LOGGER = logging.getLogger(__name__)
+
 # Compile rule per source suffix; keys must cover SRC_FILE_EXTENSIONS so any
 # source a library manifest selects has a rule (pinned by a drift test).
 _RULE_FOR_SUFFIX = {
@@ -607,6 +610,12 @@ def write_project(paths: dict[str, Path]) -> bool:
 
     for lib in libraries:
         if not lib.sources:
+            # Header-only libraries are legitimate; the log makes an empty
+            # srcFilter or broken tree traceable before link errors do.
+            _LOGGER.debug(
+                "Library %s has no source files; contributing includes only",
+                lib.name,
+            )
             continue
         lib_root = _common_parent(lib.sources)
         objs = _ninja_compile_edges(
diff --git a/script/determine-jobs.py b/script/determine-jobs.py
index ba670d0db1..6bc6d8a875 100755
--- a/script/determine-jobs.py
+++ b/script/determine-jobs.py
@@ -652,7 +652,10 @@ ESP8266_NATIVE_TRIGGER_FILES = frozenset(
 
 def _esp8266_native_path_or_file_trigger(files: list[str]) -> bool:
     """Whether any changed file is native-ESP8266 infrastructure / harness."""
-    return _path_or_file_trigger(
+    # base_python_changed covers the top-level esphome/*.py modules the
+    # native backend imports directly (framework_helpers, helpers, writer,
+    # __main__); without it a change there would silently skip this job.
+    return base_python_changed(files) or _path_or_file_trigger(
         files, ESP8266_NATIVE_TRIGGER_FILES, ESP8266_NATIVE_TRIGGER_PATH_PREFIXES
     )
 
diff --git a/tests/script/test_determine_jobs.py b/tests/script/test_determine_jobs.py
index c8ff9bd808..5aa67af73c 100644
--- a/tests/script/test_determine_jobs.py
+++ b/tests/script/test_determine_jobs.py
@@ -3083,6 +3083,9 @@ def test_esp8266_native_components_full_list_on_infra_change() -> None:
         # Shared modules the native build depends on
         ["esphome/espidf/idedata.py"],
         ["esphome/platformio/library.py"],
+        # Top-level esphome/*.py modules the backend imports directly
+        ["esphome/framework_helpers.py"],
+        ["esphome/writer.py"],
     ):
         with (
             patch.object(determine_jobs, "changed_files", return_value=changed),
diff --git a/tests/unit_tests/build_gen/test_arduino8266.py b/tests/unit_tests/build_gen/test_arduino8266.py
index 59866af6b7..3ffbf7309d 100644
--- a/tests/unit_tests/build_gen/test_arduino8266.py
+++ b/tests/unit_tests/build_gen/test_arduino8266.py
@@ -11,6 +11,7 @@ PlatformIO toolchain produces for the same configuration.
 from __future__ import annotations
 
 from collections.abc import Generator
+import logging
 from pathlib import Path
 from unittest.mock import MagicMock, patch
 
@@ -454,7 +455,9 @@ def test_generate_ld_scripts_testing_mode(tmp_path: Path) -> None:
     assert "len = 0x2000000" in patched
 
 
-def test_write_project_libraries_and_variant(tmp_path: Path) -> None:
+def test_write_project_libraries_and_variant(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
     from esphome.arduino8266.component import ArduinoLibrary
 
     paths = _make_framework(tmp_path)
@@ -477,14 +480,17 @@ def test_write_project_libraries_and_variant(tmp_path: Path) -> None:
     )
     _set_flags("-DPIO_FRAMEWORK_ARDUINO_ENABLE_EXCEPTIONS")
 
-    content = _write_ninja(
-        paths, libraries=[library, headers_only], ccache="/cc/ccache"
-    )
+    with caplog.at_level(logging.DEBUG, logger="esphome.build_gen.arduino8266"):
+        content = _write_ninja(
+            paths, libraries=[library, headers_only], ccache="/cc/ccache"
+        )
 
     assert "build libFrameworkArduinoVariant.a: ar" in content
     assert "build libMyLib.a: ar" in content
-    # A headers-only library contributes includes but no archive
+    # A headers-only library contributes includes but no archive, with a
+    # debug log distinguishing it from a resolution failure
     assert "libHeadersOnly.a" not in content
+    assert "Library HeadersOnly has no source files" in caplog.text
     assert "  flags = -DMYLIB=1" in content
     assert "-lalgobsec" in content
     # Library link flags reach the firmware link line; .cc compiles as C++
diff --git a/tests/unit_tests/test_arduino8266_component.py b/tests/unit_tests/test_arduino8266_component.py
index 28ceb5a4c3..0165ee54af 100644
--- a/tests/unit_tests/test_arduino8266_component.py
+++ b/tests/unit_tests/test_arduino8266_component.py
@@ -84,6 +84,18 @@ def test_library_info_flags_parsing(tmp_path: Path) -> None:
     assert lib.link_flags == ["-Wl,--wrap=malloc"]
 
 
+def test_library_info_missing_link_dir_warns(
+    tmp_path: Path, caplog: pytest.LogCaptureFixture
+) -> None:
+    read_path = tmp_path / "lib"
+    read_path.mkdir()
+    data = {"build": {"flags": ["-Lmissing_blobs"]}}
+    lib = component._library_info("x", read_path, data)
+    assert "declares library dir missing_blobs which does not exist" in caplog.text
+    # Kept anyway: the linker ignores missing -L dirs
+    assert lib.link_dirs == [(read_path / "missing_blobs").resolve()]
+
+
 def test_library_info_no_src_dir(tmp_path: Path) -> None:
     read_path = tmp_path / "empty"
     read_path.mkdir()