diff --git a/esphome/espidf/bootloader.py b/esphome/espidf/bootloader.py
index 07fb3c3415b..65237a371ac 100644
--- a/esphome/espidf/bootloader.py
+++ b/esphome/espidf/bootloader.py
@@ -355,6 +355,11 @@ def ensure_cached_bootloader(verbose: bool = False) -> bool:
 def _install_cached(app_config: dict, compiler: str, verbose: bool) -> Path | None:
     """The installed build/bootloader dir, building and publishing on a miss;
     None means fall back to the in-tree build."""
+    from esphome.espidf.framework import read_idf_version_txt
+
+    if not read_idf_version_txt(toolchain._get_idf_path()):
+        _LOGGER.debug("Framework version.txt missing; cannot key the bootloader")
+        return None
     if (names := _load_config_names()) is not None:
         entry = _cache_root() / _compute_key(_key_payload(names, app_config, compiler))
         if (entry / "bootloader.bin").is_file():
@@ -389,14 +394,16 @@ def _install_cached(app_config: dict, compiler: str, verbose: bool) -> Path | No
     return _install_into_build(entry)
 
 
-def inject_bootloader_flash_file(flash_data: dict, build_dir: Path) -> None:
+def inject_bootloader_flash_file(flash_data: dict, build_dir: Path) -> bool:
     """Add the cached bootloader to a flasher_args ``flash_files`` map.
 
     Gated on the tree's mode: IDF also omits the entry on purpose for some
     secure-boot builds, and those must stay exactly as IDF wrote them.
+    False means a cached-mode tree is missing pieces and the factory image
+    would not boot.
     """
     if not tree_uses_cached_bootloader(build_dir):
-        return
+        return True
     app_config = toolchain._load_sdkconfig_json(build_dir)
     if (
         app_config is None
@@ -404,6 +411,7 @@ def inject_bootloader_flash_file(flash_data: dict, build_dir: Path) -> None:
         or not (build_dir / "bootloader" / "bootloader.bin").is_file()
     ):
         _LOGGER.error("Cached bootloader missing; factory image has no bootloader")
-        return
+        return False
     flash_files = flash_data.setdefault("flash_files", {})
     flash_files[hex(_bootloader_offset(app_config))] = "bootloader/bootloader.bin"
+    return True
diff --git a/esphome/espidf/toolchain.py b/esphome/espidf/toolchain.py
index 58abfa57e0b..fd84791e1d7 100644
--- a/esphome/espidf/toolchain.py
+++ b/esphome/espidf/toolchain.py
@@ -854,7 +854,8 @@ def create_factory_bin() -> bool:
 
     from esphome.espidf import bootloader
 
-    bootloader.inject_bootloader_flash_file(flash_data, build_dir)
+    if not bootloader.inject_bootloader_flash_file(flash_data, build_dir):
+        return False
 
     # Get flash size from config
     flash_size = CORE.data[KEY_ESP32][KEY_FLASH_SIZE]
diff --git a/tests/unit_tests/test_espidf_bootloader.py b/tests/unit_tests/test_espidf_bootloader.py
index 0108771c13c..2a86e76b21c 100644
--- a/tests/unit_tests/test_espidf_bootloader.py
+++ b/tests/unit_tests/test_espidf_bootloader.py
@@ -466,6 +466,7 @@ def _orchestration_env(tmp_path: Path) -> Iterator[Path]:
         patch.object(bootloader, "_cache_root", return_value=root),
         patch.object(toolchain, "_resolved_c_compiler", return_value="/tc/gcc"),
         patch.object(bootloader, "_key_payload", return_value={}),
+        patch("esphome.espidf.framework.read_idf_version_txt", return_value="v5.5.5"),
         patch.object(bootloader, "_compute_key", return_value="deadbeefdeadbeef"),
     ):
         yield root
@@ -550,6 +551,17 @@ def test_ensure_rejects_an_unreproducible_bootloader(
     assert not list(root.glob(".build-*"))
 
 
+def test_ensure_soft_fails_without_a_version_stamp(tmp_path: Path) -> None:
+    """An unidentifiable framework install must not be keyed or cached."""
+    with (
+        _orchestration_env(tmp_path),
+        patch("esphome.espidf.framework.read_idf_version_txt", return_value=""),
+        patch.object(bootloader, "_build_standalone") as mock_build,
+    ):
+        assert bootloader.ensure_cached_bootloader() is False
+    mock_build.assert_not_called()
+
+
 def test_ensure_soft_fails_when_the_probe_build_fails(tmp_path: Path) -> None:
     rcs = iter([0, 2])
 
@@ -618,14 +630,14 @@ def _flash_build(tmp_path: Path, cached: bool = True, offset: int = 0x1000) -> P
 def test_inject_adds_cached_bootloader(tmp_path: Path) -> None:
     build = _flash_build(tmp_path)
     flash_data = {"flash_files": {"0x10000": "dev.bin"}}
-    bootloader.inject_bootloader_flash_file(flash_data, build)
+    assert bootloader.inject_bootloader_flash_file(flash_data, build) is True
     assert flash_data["flash_files"]["0x1000"] == "bootloader/bootloader.bin"
 
 
 def test_inject_uses_configured_offset(tmp_path: Path) -> None:
     build = _flash_build(tmp_path, offset=0)
     flash_data: dict = {}
-    bootloader.inject_bootloader_flash_file(flash_data, build)
+    assert bootloader.inject_bootloader_flash_file(flash_data, build) is True
     assert flash_data["flash_files"] == {"0x0": "bootloader/bootloader.bin"}
 
 
@@ -634,7 +646,7 @@ def test_inject_noop_on_a_stock_tree(tmp_path: Path) -> None:
     not in cached mode must stay exactly as IDF wrote it."""
     build = _flash_build(tmp_path, cached=False)
     flash_data: dict = {"flash_files": {}}
-    bootloader.inject_bootloader_flash_file(flash_data, build)
+    assert bootloader.inject_bootloader_flash_file(flash_data, build) is True
     assert flash_data == {"flash_files": {}}
 
 
@@ -649,7 +661,10 @@ def test_tree_uses_cached_bootloader(tmp_path: Path) -> None:
 
 def test_inject_noop_without_cmakecache(tmp_path: Path) -> None:
     flash_data: dict = {"flash_files": {}}
-    bootloader.inject_bootloader_flash_file(flash_data, tmp_path / "missing")
+    assert (
+        bootloader.inject_bootloader_flash_file(flash_data, tmp_path / "missing")
+        is True
+    )
     assert flash_data == {"flash_files": {}}
 
 
@@ -661,9 +676,9 @@ def test_inject_missing_pieces_log_an_error(
     (build / "config" / "sdkconfig.json").write_text("{}")  # no offset
     flash_data: dict = {"flash_files": {}}
     with caplog.at_level("ERROR"):
-        bootloader.inject_bootloader_flash_file(flash_data, build)
+        assert bootloader.inject_bootloader_flash_file(flash_data, build) is False
     (build / "config" / "sdkconfig.json").unlink()
     with caplog.at_level("ERROR"):
-        bootloader.inject_bootloader_flash_file(flash_data, build)
+        assert bootloader.inject_bootloader_flash_file(flash_data, build) is False
     assert flash_data == {"flash_files": {}}
     assert caplog.text.count("factory image has no bootloader") == 2
diff --git a/tests/unit_tests/test_espidf_toolchain.py b/tests/unit_tests/test_espidf_toolchain.py
index 73b951d11d6..878c93a00de 100644
--- a/tests/unit_tests/test_espidf_toolchain.py
+++ b/tests/unit_tests/test_espidf_toolchain.py
@@ -1222,6 +1222,22 @@ def test_create_factory_bin_merges_cached_bootloader(setup_core: Path) -> None:
     assert offset_index < cmd.index("0x10000")
 
 
+def test_create_factory_bin_fails_when_the_cached_bootloader_is_missing(
+    setup_core: Path,
+) -> None:
+    """A factory image without its bootloader would not boot; fail instead."""
+    _setup_build(setup_core)
+    build = CORE.relative_build_path("build")
+    build.mkdir(parents=True)
+    (build / "CMakeCache.txt").write_text(
+        "ESPHOME_USE_CACHED_BOOTLOADER:UNINITIALIZED=1\n"
+    )
+    (build / "flasher_args.json").write_text('{"flash_files": {}}')
+    with patch.object(toolchain.subprocess, "run") as mock_run:
+        assert toolchain.create_factory_bin() is False
+    mock_run.assert_not_called()
+
+
 def test_idf_target_from_variant(setup_core: Path) -> None:
     CORE.data[KEY_ESP32] = {KEY_VARIANT: "ESP32C6"}
     assert toolchain._idf_target() == "esp32c6"