diff --git a/napalm_opnsense/opnsense.py b/napalm_opnsense/opnsense.py
index 4e75d2a..084860f 100644
--- a/napalm_opnsense/opnsense.py
+++ b/napalm_opnsense/opnsense.py
@@ -2126,10 +2126,30 @@ class OPNsenseDriver(OPNsensePingMixin, FirewallDriver):
         """Remove an OPNsense plugin by name.
 
         Calls ``POST /api/core/firmware/remove/{name}``.
+
+        **Plugins only, and it says so.** ``firmware/remove`` acts on the
+        plugin set, and ``get_packages`` reads the same list — so software
+        installed as a plain FreeBSD package is invisible to the one and
+        unreachable by the other. The Wazuh agent is exactly that, on a driver
+        the agent plugin lists as supported, and during a fleet-wide rollback
+        the request posted for it could never have succeeded.
+
+        Raising beats posting. A request that cannot work reports failure for
+        the wrong reason and sends whoever reads it looking in the wrong place;
+        netOrk turns ``NotImplementedError`` into a 501, which is the accurate
+        answer. Reaching plain packages would need shell access, and the
+        credentials stored for these devices are frequently API-key only —
+        a decision of its own rather than a detail of this one.
         """
         import re as _re
         if not _re.match(r'^[a-zA-Z0-9_\-\.]+$', name):
             raise ValueError(f"Invalid package name: {name!r}")
+        if not name.startswith("os-"):
+            raise NotImplementedError(
+                f"{name!r} is not an OPNsense plugin. This driver can remove plugins "
+                "(os-*) through the firmware API; a FreeBSD package needs shell access, "
+                "which is not configured for OPNsense devices."
+            )
         try:
             result = self._post(f"/api/core/firmware/remove/{name}")
             return {"success": True, "output": str(result)}
diff --git a/tests/unit/test_driver.py b/tests/unit/test_driver.py
index 3098c6c..1729961 100644
--- a/tests/unit/test_driver.py
+++ b/tests/unit/test_driver.py
@@ -2544,3 +2544,53 @@ class TestSyncDnsZone:
 
         added = [d for p, d in calls if p.endswith("addhostoverride")]
         assert len(added) == 1
+
+
+# ---------------------------------------------------------------------------
+# uninstall_package – says what it cannot do
+# ---------------------------------------------------------------------------
+
+
+class TestUninstallPackage:
+    """`firmware/remove` reaches OPNsense plugins and nothing else.
+
+    `get_packages` reads `/api/core/firmware/info` filtered to the plugin list,
+    and `firmware/remove` acts on the same set. Software installed as a plain
+    FreeBSD package is invisible to the first and unreachable by the second —
+    the Wazuh agent being exactly that, on a driver the agent plugin lists as
+    supported.
+
+    Observed during a fleet-wide rollback on 2026-09-19: the `gw` device could
+    not be handled through netOrk at all, and the request that was posted for
+    it could never have succeeded.
+
+    So it refuses instead of posting. A request that cannot work is worse than
+    an honest no: the caller stops looking for the real problem. The API turns
+    NotImplementedError into 501, which is the accurate answer.
+    """
+
+    def test_a_plugin_is_removed(self, driver):
+        driver._post = MagicMock(return_value={"status": "ok"})
+
+        result = driver.uninstall_package("os-wazuh-agent")
+
+        assert result["success"] is True
+        driver._post.assert_called_once()
+
+    def test_a_freebsd_package_is_refused(self, driver):
+        driver._post = MagicMock()
+
+        with pytest.raises(NotImplementedError, match="plugin"):
+            driver.uninstall_package("wazuh-agent")
+
+        driver._post.assert_not_called()
+
+    def test_the_refusal_names_the_package(self, driver):
+        """Whoever reads the 501 needs to know which name was rejected."""
+        with pytest.raises(NotImplementedError, match="wazuh-agent"):
+            driver.uninstall_package("wazuh-agent")
+
+    def test_a_malformed_name_is_still_a_ValueError(self, driver):
+        """Refusing non-plugins must not swallow the injection guard."""
+        with pytest.raises(ValueError):
+            driver.uninstall_package("os-thing; rm -rf /")