Gate scoping-safety on firmware ref, and and make per-channel override tristate.

app/models.py

@@ -343,7 +343,12 @@ class Channel(BaseModel):
     on_radio: bool = False
     flood_scope_override: str | None = Field(
         default=None,
-        description="Per-channel outbound flood scope override (null = use global app setting)",
+        description=(
+            "Per-channel outbound flood scope override, tri-state: null = inherit the "
+            "global app setting; '*' (UNSCOPED_OVERRIDE_MARKER) = force unscoped/plain "
+            "flood even over a scoped global; a region name (e.g. '#Esperance') = scope "
+            "this channel."
+        ),
     )
     path_hash_mode_override: int | None = Field(
         default=None,

app/radio.py

@@ -171,6 +171,9 @@ class RadioManager:
         self.device_model: str | None = None
         self.firmware_build: str | None = None
         self.firmware_version: str | None = None
+        # Companion protocol version (FIRMWARE_VER_CODE). Gates version-dependent
+        # host commands such as the mode-1 unscoped flood-scope frame (ver 12+).
+        self.firmware_ver_code: int | None = None
         self.max_channels: int = 40
         self.path_hash_mode: int = 0
         self.path_hash_mode_supported: bool = False
@@ -217,6 +220,7 @@ class RadioManager:
         self.device_model = None
         self.firmware_build = None
         self.firmware_version = None
+        self.firmware_ver_code = None
         self.max_channels = 40
         self.path_hash_mode = 0
         self.path_hash_mode_supported = False

app/region_scope.py

@@ -1,6 +1,22 @@
 """Helpers for normalizing MeshCore flood-scope / region names."""
 
-_UNSCOPED_SENTINELS = {"", "0", "*"}
+# Canonical persisted marker for "force unscoped/plain flood". Stored verbatim in
+# the per-channel ``flood_scope_override`` column to mean "this channel is unscoped
+# even if a global region is set" — distinct from NULL, which means "inherit global".
+UNSCOPED_OVERRIDE_MARKER = "*"
+
+# All values that denote explicit unscoped/plain flood, matching firmware parity.
+_UNSCOPED_SENTINELS = {"", "0", UNSCOPED_OVERRIDE_MARKER}
+
+
+def is_unscoped(scope: str | None) -> bool:
+    """True if ``scope`` denotes an explicit unscoped/plain-flood request.
+
+    Note: an empty string counts as unscoped here. Callers that need to treat
+    blank as "no opinion / inherit" (e.g. the channel-override API) must check for
+    blank *before* calling this.
+    """
+    return (scope or "").strip() in _UNSCOPED_SENTINELS
 
 
 def normalize_region_scope(scope: str | None) -> str:

app/routers/channels.py

@@ -14,7 +14,7 @@ from app.channel_constants import (
 from app.decoder import parse_packet, try_decrypt_packet_with_channel_key
 from app.models import Channel, ChannelDetail, ChannelMessageCounts, ChannelTopSender
 from app.packet_processor import create_message_from_decrypted
-from app.region_scope import normalize_region_scope
+from app.region_scope import UNSCOPED_OVERRIDE_MARKER, is_unscoped, normalize_region_scope
 from app.repository import ChannelRepository, MessageRepository, RawPacketRepository
 from app.websocket import broadcast_event, broadcast_success
 
@@ -56,7 +56,13 @@ class BulkCreateHashtagChannelsResponse(BaseModel):
 
 class ChannelFloodScopeOverrideRequest(BaseModel):
     flood_scope_override: str = Field(
-        description="Blank clears the override; non-empty values temporarily override flood scope"
+        description=(
+            "Tri-state channel override. Blank clears the override (inherit the global "
+            "scope); '*' forces unscoped/plain flood even when a global region is set; "
+            "any other value scopes the channel to that region. Note the deliberate "
+            "asymmetry vs. the send layer: here blank means 'inherit', so an explicit "
+            "unscoped request must use '*'."
+        )
     )
 
 
@@ -345,7 +351,19 @@ async def set_channel_flood_scope_override(
     if not channel:
         raise HTTPException(status_code=404, detail="Channel not found")
 
-    override = normalize_region_scope(request.flood_scope_override) or None
+    # Tri-state persisted override:
+    #   blank        -> None: clear the override, inherit the global scope
+    #   "*" / "0"    -> canonical unscoped marker: force unscoped even over a global
+    #   region name  -> "#Region": scope this channel
+    # NOTE: at this (channel-override) layer blank means "clear/inherit", so we must
+    # check for blank *before* is_unscoped() (which also treats "" as unscoped).
+    raw_override = (request.flood_scope_override or "").strip()
+    if raw_override == "":
+        override: str | None = None
+    elif is_unscoped(raw_override):
+        override = UNSCOPED_OVERRIDE_MARKER
+    else:
+        override = normalize_region_scope(raw_override)
     updated = await ChannelRepository.update_flood_scope_override(channel.key, override)
     if not updated:
         raise HTTPException(status_code=500, detail="Failed to update flood-scope override")

app/routers/settings.py

@@ -289,7 +289,9 @@ async def update_settings(update: AppSettingsUpdate) -> AppSettings:
                 try:
                     scope = result.flood_scope
                     async with radio_manager.radio_operation("set_flood_scope") as mc:
-                        await set_radio_flood_scope(mc, scope)
+                        await set_radio_flood_scope(
+                            mc, scope, fw_ver=radio_manager.firmware_ver_code
+                        )
                         logger.info("Applied flood_scope=%r to radio", scope or "(disabled)")
                 except Exception as e:
                     logger.warning("Failed to apply flood_scope to radio: %s", e)

app/services/flood_scope.py

@@ -1,5 +1,6 @@
 """Firmware-compatible flood-scope command helpers."""
 
+import logging
 from typing import Any
 
 from meshcore import EventType
@@ -7,23 +8,50 @@ from meshcore.packets import CommandType
 
 from app.region_scope import normalize_region_scope
 
+logger = logging.getLogger(__name__)
+
 SET_FLOOD_SCOPE_MODE_UNSCOPED = 1
 FORCE_UNSCOPED_FRAME = bytes([CommandType.SET_FLOOD_SCOPE.value, SET_FLOOD_SCOPE_MODE_UNSCOPED])
 
+# CMD_SET_FLOOD_SCOPE_KEY mode 1 (the firmware ``send_unscoped`` flag) is companion
+# firmware ver 12+. On older firmware the mode-1 frame is rejected, so we fall back
+# to resetting the scope override (mode 0, zero key), which makes the radio use its
+# configured default scope. True "unscoped while a default scope is set" is not
+# achievable pre-v12.
+FIRMWARE_VER_UNSCOPED_MODE = 12
 
-async def set_radio_flood_scope(mc, scope: str | None) -> Any:
+
+def firmware_supports_unscoped_mode(fw_ver: int | None) -> bool:
+    """Whether the radio's protocol version supports the mode-1 unscoped command."""
+    return fw_ver is not None and fw_ver >= FIRMWARE_VER_UNSCOPED_MODE
+
+
+async def set_radio_flood_scope(mc, scope: str | None, *, fw_ver: int | None = None) -> Any:
     """Apply the standing radio flood-scope state.
 
-    A non-empty scope is delegated to meshcore_py's mode-0 ``set_flood_scope``.
-    An empty scope means explicit unscoped/plain flood and must use firmware's
-    mode-1 command. Sending a mode-0 all-zero key would fall back to the radio's
-    configured default scope on firmware-compatible companions.
-    """
+    A non-empty scope is delegated to meshcore_py's mode-0 ``set_flood_scope``. An
+    empty scope means explicit unscoped/plain flood:
 
+    - firmware >= 12: use the dedicated mode-1 command (``force_radio_unscoped``).
+    - older / unknown firmware: no dedicated unscoped command exists, so reset the
+      scope override (mode 0, zero key); the radio falls back to its configured
+      default scope. ``fw_ver=None`` (version unknown) is treated conservatively as
+      unsupported so we never emit a frame the radio might reject.
+    """
     normalized_scope = normalize_region_scope(scope)
     if normalized_scope:
         return await mc.commands.set_flood_scope(normalized_scope)
-    return await force_radio_unscoped(mc)
+
+    if firmware_supports_unscoped_mode(fw_ver):
+        return await force_radio_unscoped(mc)
+
+    logger.debug(
+        "Radio fw_ver=%s < %d: no dedicated unscoped command; resetting scope override "
+        "(radio falls back to its configured default scope)",
+        fw_ver,
+        FIRMWARE_VER_UNSCOPED_MODE,
+    )
+    return await mc.commands.set_flood_scope("")
 
 
 async def force_radio_unscoped(mc) -> Any:

app/services/message_send.py

@@ -11,7 +11,7 @@ from meshcore import EventType
 
 from app.models import ResendChannelMessageResponse
 from app.radio import RadioOperationBusyError
-from app.region_scope import normalize_region_scope
+from app.region_scope import is_unscoped, normalize_region_scope
 from app.repository import (
     AppSettingsRepository,
     ChannelRepository,
@@ -161,8 +161,20 @@ async def send_channel_message_with_effective_scope(
     back to the channel's persisted override.
     """
     if isinstance(flood_scope_override, _ScopeUnset):
-        desired_scope = normalize_region_scope(channel.flood_scope_override)
-        scope_explicit = False
+        # Fall back to the channel's persisted override, which is tri-state:
+        #   None -> inherit the global scope (leave radio untouched)
+        #   unscoped marker ("*") -> force unscoped even over a scoped global
+        #   region name -> scope this channel
+        channel_override = channel.flood_scope_override
+        if channel_override is None:
+            desired_scope = ""
+            scope_explicit = False
+        elif is_unscoped(channel_override):
+            desired_scope = ""
+            scope_explicit = True
+        else:
+            desired_scope = normalize_region_scope(channel_override)
+            scope_explicit = True
     else:
         desired_scope = normalize_region_scope(flood_scope_override)
         scope_explicit = True
@@ -185,7 +197,9 @@ async def send_channel_message_with_effective_scope(
             desired_scope or "(unscoped)",
             channel.name,
         )
-        override_result = await set_radio_flood_scope(mc, desired_scope)
+        override_result = await set_radio_flood_scope(
+            mc, desired_scope, fw_ver=radio_manager.firmware_ver_code
+        )
         if override_result is not None and override_result.type == EventType.ERROR:
             logger.warning(
                 "Failed to apply flood_scope %r for %s: %s",
@@ -314,7 +328,9 @@ async def send_channel_message_with_effective_scope(
             restored = False
             for attempt in range(3):
                 try:
-                    restore_result = await set_radio_flood_scope(mc, baseline_scope)
+                    restore_result = await set_radio_flood_scope(
+                        mc, baseline_scope, fw_ver=radio_manager.firmware_ver_code
+                    )
                     if restore_result is not None and restore_result.type == EventType.ERROR:
                         logger.warning(
                             "Attempt %d/3: failed to restore flood_scope after sending to %s: %s",

app/services/radio_lifecycle.py

@@ -67,20 +67,6 @@ async def run_post_connect_setup(radio_manager) -> None:
                 # Sync radio clock with system time
                 await sync_radio_time(mc)
 
-                # Apply flood scope from settings (best-effort; older firmware
-                # may not support the relevant flood-scope command)
-                from app.region_scope import normalize_region_scope
-                from app.repository import AppSettingsRepository
-                from app.services.flood_scope import set_radio_flood_scope
-
-                app_settings = await AppSettingsRepository.get()
-                scope = normalize_region_scope(app_settings.flood_scope)
-                try:
-                    await set_radio_flood_scope(mc, scope)
-                    logger.info("Applied flood_scope=%r", scope or "(disabled)")
-                except Exception as exc:
-                    logger.warning("Failed to apply configured flood scope to radio: %s", exc)
-
                 # Query path hash mode support (best-effort; older firmware won't report it).
                 # If the library's parsed payload is missing path_hash_mode (e.g. stale
                 # .pyc on WSL2 Windows mounts), fall back to raw-frame extraction.
@@ -101,6 +87,7 @@ async def run_post_connect_setup(radio_manager) -> None:
                 radio_manager.device_model = None
                 radio_manager.firmware_build = None
                 radio_manager.firmware_version = None
+                radio_manager.firmware_ver_code = None
                 radio_manager.max_channels = 40
                 radio_manager.path_hash_mode = 0
                 radio_manager.path_hash_mode_supported = False
@@ -128,6 +115,7 @@ async def run_post_connect_setup(radio_manager) -> None:
                     payload_reports_device_info = isinstance(fw_ver, int) and fw_ver >= 3
                     if payload_reports_device_info:
                         radio_manager.device_info_loaded = True
+                        radio_manager.firmware_ver_code = fw_ver
 
                     if "path_hash_mode" in payload and isinstance(payload["path_hash_mode"], int):
                         radio_manager.path_hash_mode = payload["path_hash_mode"]
@@ -141,6 +129,7 @@ async def run_post_connect_setup(radio_manager) -> None:
                         fw_ver = raw[1] if len(raw) > 1 else 0
                         if fw_ver >= 3:
                             radio_manager.device_info_loaded = True
+                            radio_manager.firmware_ver_code = fw_ver
                             if radio_manager.max_contacts is None and len(raw) >= 3:
                                 radio_manager.max_contacts = max(1, raw[2] * 2)
                             if len(raw) >= 4 and not isinstance(payload_max_channels, int):
@@ -206,6 +195,22 @@ async def run_post_connect_setup(radio_manager) -> None:
                 finally:
                     reader.handle_rx = _original_handle_rx
 
+                # Apply flood scope from settings (best-effort; older firmware may
+                # not support the mode-1 unscoped command). Done after the device
+                # query so radio_manager.firmware_ver_code is known and the unscoped
+                # path can pick the correct firmware command.
+                from app.region_scope import normalize_region_scope
+                from app.repository import AppSettingsRepository
+                from app.services.flood_scope import set_radio_flood_scope
+
+                app_settings = await AppSettingsRepository.get()
+                scope = normalize_region_scope(app_settings.flood_scope)
+                try:
+                    await set_radio_flood_scope(mc, scope, fw_ver=radio_manager.firmware_ver_code)
+                    logger.info("Applied flood_scope=%r", scope or "(disabled)")
+                except Exception as exc:
+                    logger.warning("Failed to apply configured flood scope to radio: %s", exc)
+
                 from app.config import settings as app_settings_config
 
                 if app_settings_config.skip_post_connect_sync:

frontend/src/components/ChannelFloodScopeOverrideModal.tsx

@@ -1,6 +1,10 @@
 import { useEffect, useState } from 'react';
 
-import { stripRegionScopePrefix } from '../utils/regionScope';
+import {
+  UNSCOPED_OVERRIDE_MARKER,
+  isUnscopedMarker,
+  stripRegionScopePrefix,
+} from '../utils/regionScope';
 import { Button } from './ui/button';
 import {
   Dialog,
@@ -34,11 +38,18 @@ export function ChannelFloodScopeOverrideModal({
     if (!open) {
       return;
     }
-    setRegion(stripRegionScopePrefix(currentOverride));
+    // The unscoped marker isn't a region name, so start the input blank for it.
+    setRegion(isUnscopedMarker(currentOverride) ? '' : stripRegionScopePrefix(currentOverride));
   }, [currentOverride, open]);
 
   const trimmedRegion = region.trim();
 
+  const currentOverrideLabel = isUnscopedMarker(currentOverride)
+    ? 'unscoped (plain flood)'
+    : currentOverride
+      ? stripRegionScopePrefix(currentOverride)
+      : 'inherit global setting';
+
   return (
     <Dialog open={open} onOpenChange={(isOpen) => !isOpen && onClose()}>
       <DialogContent className="sm:max-w-[520px]">
@@ -46,7 +57,9 @@ export function ChannelFloodScopeOverrideModal({
           <DialogTitle>Regional Override</DialogTitle>
           <DialogDescription>
             Channel-level regional routing temporarily changes the radio flood scope before send and
-            restores it after. This can noticeably slow channel sends.
+            restores it after. This can noticeably slow channel sends. Choose one of three modes
+            below: scope to a region, force unscoped (plain flood, ignoring your global region), or
+            inherit the global setting.
           </DialogDescription>
         </DialogHeader>
 
@@ -54,8 +67,7 @@ export function ChannelFloodScopeOverrideModal({
           <div className="rounded-md border border-border bg-muted/20 p-3 text-sm">
             <div className="font-medium">{roomName}</div>
             <div className="mt-1 text-muted-foreground">
-              Current regional override:{' '}
-              {currentOverride ? stripRegionScopePrefix(currentOverride) : 'none'}
+              Current setting: {currentOverrideLabel}
             </div>
           </div>
 
@@ -83,8 +95,19 @@ export function ChannelFloodScopeOverrideModal({
               }}
             >
               {trimmedRegion.length > 0
-                ? `Use ${trimmedRegion} region for ${roomName}`
-                : `Use region for ${roomName}`}
+                ? `Scope ${roomName} to ${trimmedRegion}`
+                : `Scope ${roomName} to a region`}
+            </Button>
+            <Button
+              type="button"
+              variant="outline"
+              className="w-full"
+              onClick={() => {
+                onSetOverride(UNSCOPED_OVERRIDE_MARKER);
+                onClose();
+              }}
+            >
+              Always send {roomName} unscoped (ignore global region)
             </Button>
             <Button
               type="button"
@@ -95,7 +118,7 @@ export function ChannelFloodScopeOverrideModal({
                 onClose();
               }}
             >
-              Do not use region routing for {roomName}
+              Use global region setting for {roomName}
             </Button>
           </div>
         </DialogFooter>

frontend/src/components/settings/SettingsRadioSection.tsx

@@ -1163,7 +1163,9 @@ export function SettingsRadioSection({
         <p className="text-[0.8125rem] text-muted-foreground">
           Tag outgoing messages with a region name (e.g. MyRegion). Repeaters configured for that
           region can forward the traffic, while repeaters configured to deny other regions may drop
-          it. Leave empty to disable.
+          it. Leave empty to send unscoped (plain flood). Forcing unscoped when a default scope is
+          configured on the radio requires firmware v12 or newer. Individual channels can override
+          this with their own region or an "always unscoped" setting.
         </p>
       </div>
 

frontend/src/test/chatHeaderKeyVisibility.test.tsx

@@ -360,8 +360,34 @@ describe('ChatHeader key visibility', () => {
 
     expect(await screen.findByRole('dialog')).toBeInTheDocument();
     fireEvent.change(screen.getByLabelText('Region'), { target: { value: 'Esperance' } });
-    fireEvent.click(screen.getByRole('button', { name: 'Use Esperance region for #flightless' }));
+    fireEvent.click(screen.getByRole('button', { name: 'Scope #flightless to Esperance' }));
 
     expect(onSetChannelFloodScopeOverride).toHaveBeenCalledWith(key, 'Esperance');
   });
+
+  it('forces the channel unscoped via the modal (issue #303)', async () => {
+    const key = 'CD'.repeat(16);
+    const channel = makeChannel(key, '#flightless', true);
+    const conversation: Conversation = { type: 'channel', id: key, name: '#flightless' };
+    const onSetChannelFloodScopeOverride = vi.fn();
+
+    render(
+      <ChatHeader
+        {...baseProps}
+        conversation={conversation}
+        channels={[channel]}
+        onSetChannelFloodScopeOverride={onSetChannelFloodScopeOverride}
+      />
+    );
+
+    fireEvent.click(screen.getByTitle('Set regional override'));
+    expect(await screen.findByRole('dialog')).toBeInTheDocument();
+    fireEvent.click(
+      screen.getByRole('button', {
+        name: 'Always send #flightless unscoped (ignore global region)',
+      })
+    );
+
+    expect(onSetChannelFloodScopeOverride).toHaveBeenCalledWith(key, '*');
+  });
 });

frontend/src/utils/regionScope.ts

@@ -1,3 +1,12 @@
+// Canonical persisted marker meaning "force this channel unscoped / plain flood"
+// (mirrors the backend UNSCOPED_OVERRIDE_MARKER). Distinct from null, which means
+// "inherit the global scope".
+export const UNSCOPED_OVERRIDE_MARKER = '*';
+
+export function isUnscopedMarker(scope: string | null | undefined): boolean {
+  return scope === UNSCOPED_OVERRIDE_MARKER;
+}
+
 export function stripRegionScopePrefix(scope: string | null | undefined): string {
   if (!scope) return '';
   return scope.startsWith('#') ? scope.slice(1) : scope;

tests/test_channels_router.py

@@ -32,6 +32,26 @@ class TestChannelFloodScopeOverride:
         mock_broadcast.assert_called_once()
         assert mock_broadcast.call_args.args[0] == "channel"
 
+    @pytest.mark.asyncio
+    async def test_unscoped_marker_forces_channel_unscoped(self, test_db, client):
+        """'*' persists as the canonical unscoped marker (issue #303), distinct
+        from blank (which clears the override / inherits the global scope)."""
+        key = "DD" * 16
+        await ChannelRepository.upsert(key=key, name="#flightless", is_hashtag=True)
+
+        with patch("app.routers.channels.broadcast_event"):
+            response = await client.post(
+                f"/api/channels/{key}/flood-scope-override",
+                json={"flood_scope_override": "*"},
+            )
+
+        assert response.status_code == 200
+        assert response.json()["flood_scope_override"] == "*"
+
+        channel = await ChannelRepository.get_by_key(key)
+        assert channel is not None
+        assert channel.flood_scope_override == "*"
+
 
 class TestCreateChannel:
     @pytest.mark.asyncio

tests/test_flood_scope_service.py

@@ -3,7 +3,17 @@ from unittest.mock import AsyncMock, MagicMock
 import pytest
 from meshcore import EventType
 
-from app.services.flood_scope import FORCE_UNSCOPED_FRAME, set_radio_flood_scope
+from app.services.flood_scope import (
+    FIRMWARE_VER_UNSCOPED_MODE,
+    FORCE_UNSCOPED_FRAME,
+    firmware_supports_unscoped_mode,
+    set_radio_flood_scope,
+)
+
+# A protocol version that supports the mode-1 unscoped command (>= 12).
+FW_SUPPORTS_UNSCOPED = FIRMWARE_VER_UNSCOPED_MODE
+# A protocol version that predates the mode-1 command.
+FW_NO_UNSCOPED = FIRMWARE_VER_UNSCOPED_MODE - 1
 
 
 @pytest.mark.asyncio
@@ -12,7 +22,8 @@ async def test_set_radio_flood_scope_uses_meshcore_scope_for_regions():
     mc.commands.set_flood_scope = AsyncMock(return_value="ok")
     mc.commands.send = AsyncMock()
 
-    result = await set_radio_flood_scope(mc, "Esperance")
+    # Region path is version-independent.
+    result = await set_radio_flood_scope(mc, "Esperance", fw_ver=FW_NO_UNSCOPED)
 
     assert result == "ok"
     mc.commands.set_flood_scope.assert_awaited_once_with("#Esperance")
@@ -20,12 +31,12 @@ async def test_set_radio_flood_scope_uses_meshcore_scope_for_regions():
 
 
 @pytest.mark.asyncio
-async def test_set_radio_flood_scope_empty_uses_firmware_unscoped_mode():
+async def test_set_radio_flood_scope_empty_uses_firmware_unscoped_mode_on_v12():
     mc = MagicMock()
     mc.commands.set_flood_scope = AsyncMock()
     mc.commands.send = AsyncMock(return_value="ok")
 
-    result = await set_radio_flood_scope(mc, "")
+    result = await set_radio_flood_scope(mc, "", fw_ver=FW_SUPPORTS_UNSCOPED)
 
     assert result == "ok"
     mc.commands.send.assert_awaited_once_with(FORCE_UNSCOPED_FRAME, [EventType.OK, EventType.ERROR])
@@ -34,13 +45,35 @@ async def test_set_radio_flood_scope_empty_uses_firmware_unscoped_mode():
 
 @pytest.mark.asyncio
 @pytest.mark.parametrize("scope", [None, "   ", "0", "*"])
-async def test_set_radio_flood_scope_unscoped_sentinels_use_firmware_mode(scope):
+async def test_set_radio_flood_scope_unscoped_sentinels_use_firmware_mode_on_v12(scope):
     mc = MagicMock()
     mc.commands.set_flood_scope = AsyncMock()
     mc.commands.send = AsyncMock(return_value="ok")
 
-    result = await set_radio_flood_scope(mc, scope)
+    result = await set_radio_flood_scope(mc, scope, fw_ver=FW_SUPPORTS_UNSCOPED)
 
     assert result == "ok"
     mc.commands.send.assert_awaited_once_with(FORCE_UNSCOPED_FRAME, [EventType.OK, EventType.ERROR])
     mc.commands.set_flood_scope.assert_not_awaited()
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("fw_ver", [None, FW_NO_UNSCOPED])
+async def test_set_radio_flood_scope_unscoped_falls_back_on_old_or_unknown_firmware(fw_ver):
+    """Pre-v12 (or unknown) firmware has no mode-1 command; reset scope via mode 0."""
+    mc = MagicMock()
+    mc.commands.set_flood_scope = AsyncMock(return_value="ok")
+    mc.commands.send = AsyncMock()
+
+    result = await set_radio_flood_scope(mc, "", fw_ver=fw_ver)
+
+    assert result == "ok"
+    mc.commands.set_flood_scope.assert_awaited_once_with("")
+    mc.commands.send.assert_not_awaited()
+
+
+def test_firmware_supports_unscoped_mode():
+    assert firmware_supports_unscoped_mode(FIRMWARE_VER_UNSCOPED_MODE) is True
+    assert firmware_supports_unscoped_mode(FIRMWARE_VER_UNSCOPED_MODE + 1) is True
+    assert firmware_supports_unscoped_mode(FIRMWARE_VER_UNSCOPED_MODE - 1) is False
+    assert firmware_supports_unscoped_mode(None) is False

tests/test_radio.py

@@ -981,6 +981,11 @@ class TestPostConnectSetupOrdering:
         mock_mc.start_auto_message_fetching = AsyncMock()
         mock_mc.commands.set_flood_scope = AsyncMock()
         mock_mc.commands.send = AsyncMock()
+        # Flood scope is applied after the device query, so report a protocol
+        # version that supports the mode-1 unscoped command (>= 12).
+        device_query = MagicMock()
+        device_query.payload = {"fw ver": 13}
+        mock_mc.commands.send_device_query = AsyncMock(return_value=device_query)
         rm._meshcore = mock_mc
 
         mock_settings = AppSettings(flood_scope="")

tests/test_region_scope.py

@@ -1,4 +1,8 @@
-from app.region_scope import normalize_region_scope
+from app.region_scope import (
+    UNSCOPED_OVERRIDE_MARKER,
+    is_unscoped,
+    normalize_region_scope,
+)
 
 
 def test_normalize_region_scope_preserves_regions():
@@ -12,3 +16,20 @@ def test_normalize_region_scope_unscoped_sentinels():
     assert normalize_region_scope("   ") == ""
     assert normalize_region_scope("0") == ""
     assert normalize_region_scope("*") == ""
+
+
+def test_is_unscoped():
+    assert is_unscoped(None) is True
+    assert is_unscoped("") is True
+    assert is_unscoped("   ") is True
+    assert is_unscoped("0") is True
+    assert is_unscoped("*") is True
+    assert is_unscoped(UNSCOPED_OVERRIDE_MARKER) is True
+    assert is_unscoped("Esperance") is False
+    assert is_unscoped("#Esperance") is False
+
+
+def test_unscoped_override_marker_is_recognized_and_not_a_region():
+    # The canonical persisted marker must round-trip as unscoped, never as a region.
+    assert is_unscoped(UNSCOPED_OVERRIDE_MARKER) is True
+    assert normalize_region_scope(UNSCOPED_OVERRIDE_MARKER) == ""

tests/test_send_messages.py

@@ -664,6 +664,7 @@ class TestOutgoingChannelBroadcast:
         with (
             patch("app.routers.messages.radio_manager.require_connected", return_value=mc),
             patch.object(radio_manager, "_meshcore", mc),
+            patch.object(radio_manager, "firmware_ver_code", 13),
             patch("app.routers.messages.broadcast_event"),
         ):
             request = SendChannelMessageRequest(
@@ -689,6 +690,7 @@ class TestOutgoingChannelBroadcast:
         with (
             patch("app.routers.messages.radio_manager.require_connected", return_value=mc),
             patch.object(radio_manager, "_meshcore", mc),
+            patch.object(radio_manager, "firmware_ver_code", 13),
             patch("app.routers.messages.broadcast_event"),
         ):
             request = SendChannelMessageRequest(
@@ -702,6 +704,33 @@ class TestOutgoingChannelBroadcast:
         ]
         assert mc.commands.set_flood_scope.await_args_list == [call("#Baseline")]
 
+    @pytest.mark.asyncio
+    async def test_persisted_unscoped_channel_forces_plain_flood_over_scoped_global(self, test_db):
+        """A channel persistently marked unscoped ('*') sends unscoped even when the
+        companion has a global region set — the core of issue #303. No per-send
+        override is supplied, so this exercises the persisted-override path."""
+        mc = _make_mc(name="MyNode")
+        chan_key = "d3" * 16
+        await ChannelRepository.upsert(key=chan_key, name="#plain")
+        await ChannelRepository.update_flood_scope_override(chan_key, "*")
+        await AppSettingsRepository.update(flood_scope="Baseline")
+
+        with (
+            patch("app.routers.messages.radio_manager.require_connected", return_value=mc),
+            patch.object(radio_manager, "_meshcore", mc),
+            patch.object(radio_manager, "firmware_ver_code", 13),
+            patch("app.routers.messages.broadcast_event"),
+        ):
+            # No per-send flood_scope_override: fall back to the channel's persisted "*".
+            request = SendChannelMessageRequest(channel_key=chan_key, text="hello")
+            await send_channel_message(request)
+
+        # Force unscoped via mode 1, then restore the global region baseline.
+        assert mc.commands.send.await_args_list == [
+            call(FORCE_UNSCOPED_FRAME, [EventType.OK, EventType.ERROR])
+        ]
+        assert mc.commands.set_flood_scope.await_args_list == [call("#Baseline")]
+
     @pytest.mark.asyncio
     async def test_send_channel_msg_aborts_when_override_apply_fails(self, test_db):
         mc = _make_mc(name="MyNode")

tests/test_settings_router.py

@@ -142,6 +142,7 @@ class TestUpdateSettings:
         mock_rm = AsyncMock()
         mock_rm.is_connected = True
         mock_rm.meshcore = mock_mc
+        mock_rm.firmware_ver_code = 13  # supports mode-1 unscoped
 
         from contextlib import asynccontextmanager
 
@@ -168,6 +169,7 @@ class TestUpdateSettings:
         mock_rm = AsyncMock()
         mock_rm.is_connected = True
         mock_rm.meshcore = mock_mc
+        mock_rm.firmware_ver_code = 13  # supports mode-1 unscoped
 
         from contextlib import asynccontextmanager