diff --git a/dotbot/cli/device.py b/dotbot/cli/device.py
index 7b9aed5f..6448d40b 100644
--- a/dotbot/cli/device.py
+++ b/dotbot/cli/device.py
@@ -114,6 +114,19 @@ def _fw_version_option(f):
     )(f)
 
 
+def _local_root_option(f):
+    return click.option(
+        "--local-root",
+        type=click.Path(path_type=Path, file_okay=False, dir_okay=True),
+        default=None,
+        help=(
+            "With -f local: root of the build tree to flash from (e.g. a "
+            "worktree). Re-links the local artifacts before flashing, so this "
+            "is `dotbot fw fetch -f local --local-root <path>` in one step."
+        ),
+    )(f)
+
+
 @cmd.command(name="flash-swarmit-sandbox")
 @click.option(
     "--swarm-id",
@@ -128,9 +141,12 @@ def _fw_version_option(f):
     help="Optional LH2 calibration file to bake into the config page.",
 )
 @_fw_version_option
+@_local_root_option
 @_probe_option
 @click.pass_context
-def flash_swarmit_sandbox(ctx, swarm_id, calibration_path, fw_version, probe):
+def flash_swarmit_sandbox(
+    ctx, swarm_id, calibration_path, fw_version, local_root, probe
+):
     """Turn a DotBot v3 into a swarm sandbox host (was `provision -d dotbot-v3`).
 
     Flashes the SwarmIT bootloader (app core) + netcore + writes the
@@ -161,6 +177,7 @@ def flash_swarmit_sandbox(ctx, swarm_id, calibration_path, fw_version, probe):
         calibration_path=calibration_path,
         bin_dir=artifacts_dir(),
         sn_starting_digits=probe,
+        local_root=local_root,
     )
 
 
@@ -171,9 +188,10 @@ def flash_swarmit_sandbox(ctx, swarm_id, calibration_path, fw_version, probe):
     help="16-bit hex swarm id (e.g. 0100); defaults to your config's swarm_id.",
 )
 @_fw_version_option
+@_local_root_option
 @_probe_option
 @click.pass_context
-def flash_mari_gateway(ctx, swarm_id, fw_version, probe):
+def flash_mari_gateway(ctx, swarm_id, fw_version, local_root, probe):
     """Turn an nRF5340-DK into the swarm gateway (was `provision -d gateway`).
 
     Flashes the Mari gateway firmware (both cores) + writes the network
@@ -203,6 +221,7 @@ def flash_mari_gateway(ctx, swarm_id, fw_version, probe):
         fw_version=fw_version,
         bin_dir=artifacts_dir(),
         sn_starting_digits=probe,
+        local_root=local_root,
     )
 
 
diff --git a/dotbot/firmware/flash.py b/dotbot/firmware/flash.py
index 17e2e67b..1e8019b3 100644
--- a/dotbot/firmware/flash.py
+++ b/dotbot/firmware/flash.py
@@ -297,6 +297,23 @@ def manifest_matches(
     )
 
 
+def describe_image(path: Path) -> str:
+    """``path``, plus the symlink target and its build time when it is a link.
+
+    ``-f local`` resolves to a directory of symlinks into a build tree, so the
+    path alone does not say which tree (or how stale a build) is about to be
+    flashed. Resolving it here means every flash reports its own provenance.
+    """
+    if not path.is_symlink():
+        return str(path)
+    target = Path(os.readlink(path))
+    try:
+        built = time.strftime("%Y-%m-%d %H:%M", time.localtime(target.stat().st_mtime))
+    except OSError:
+        return f"{path} -> {target} (BROKEN LINK)"
+    return f"{path}\n              -> {target} (built {built})"
+
+
 def flash_role(
     role: str,
     *,
@@ -306,6 +323,7 @@ def flash_role(
     bin_dir: Path = DEFAULT_BIN_DIR,
     sn_starting_digits: str | None = None,
     default_app_name: str | None = None,
+    local_root: Path | None = None,
 ) -> None:
     """Flash a device's role: system firmware bundle (app+net cores) + config.
 
@@ -316,10 +334,19 @@ def flash_role(
     net_id/device_id (never raises on readback failure). If the role's
     images are absent from ``bin_dir/<fw_version>/``, fetches the release
     first (the "run fetch under the hood" behaviour).
+
+    ``local_root`` (only with ``fw_version="local"``) re-points the local
+    symlinks at that build tree before flashing, so a one-liner can target a
+    worktree instead of whichever tree a previous `dotbot fw fetch` linked.
     """
     assets = DEVICE_ASSETS[role]
     net_id_val, net_id_hex = net_id
 
+    # Checked before the J-Link probe so a bad flag combination fails
+    # instantly rather than after hardware selection.
+    if local_root is not None and fw_version != "local":
+        raise click.ClickException("--local-root requires --fw-version local.")
+
     if sn_starting_digits:
         snr = pick_matching_jlink_snr(sn_starting_digits)
     else:
@@ -370,7 +397,9 @@ def flash_role(
     # swarmit release into bin_dir/swarmit-<version>/ before flashing.
     pre_app = fw_root / assets["app"]
     pre_net = fw_root / assets["net"]
-    if fw_version != "local" and not (pre_app.exists() and pre_net.exists()):
+    if fw_version == "local" and local_root is not None:
+        fetch_assets("swarmit", "local", bin_dir, local_root)
+    elif fw_version != "local" and not (pre_app.exists() and pre_net.exists()):
         click.echo(f"[INFO] firmware {fw_version} not found in {fw_root}; fetching...")
         fetch_assets("swarmit", fw_version, bin_dir)
     if not fw_root.exists():
@@ -447,8 +476,8 @@ def flash_role(
     click.echo(f"[INFO] device: {device}")
     click.echo(f"[INFO] fw_version: {fw_version}")
     click.echo(f"[INFO] network_id: 0x{net_id_hex}")
-    click.echo(f"[INFO] app hex: {app_hex}")
-    click.echo(f"[INFO] net hex: {net_hex}")
+    click.echo(f"[INFO] app hex: {describe_image(app_hex)}")
+    click.echo(f"[INFO] net hex: {describe_image(net_hex)}")
     click.echo(f"[INFO] config hex: {config_hex}")
 
     if not config_hex.exists():