diff --git a/scripts/bootstrap_canopy.py b/scripts/bootstrap_canopy.py
index 491f7c0..c8a68e6 100644
--- a/scripts/bootstrap_canopy.py
+++ b/scripts/bootstrap_canopy.py
@@ -4,6 +4,7 @@ from __future__ import annotations
 
 import argparse
 import json
+import time
 from collections.abc import Iterable
 from pathlib import Path
 from typing import Any
@@ -142,7 +143,43 @@ def destination_for(url: str, output_dir: Path) -> Path:
     return output_dir / name
 
 
-def download_urls(urls: list[str], output_dir: Path, overwrite: bool) -> tuple[int, int, list[str]]:
+def _format_mb(value: int) -> str:
+    return f"{value / (1024 * 1024):.1f} MB"
+
+
+def _download_one(url: str, destination: Path, timeout_s: int, chunk_size: int) -> None:
+    partial = destination.with_suffix(f"{destination.suffix}.part")
+    request = Request(url, headers={"User-Agent": USER_AGENT})
+    with urlopen(request, timeout=timeout_s) as response, partial.open("wb") as output:
+        total_header = response.headers.get("Content-Length")
+        total = int(total_header) if total_header and total_header.isdigit() else None
+        read = 0
+        last_report = time.monotonic()
+        while True:
+            chunk = response.read(chunk_size)
+            if not chunk:
+                break
+            output.write(chunk)
+            read += len(chunk)
+            now = time.monotonic()
+            if now - last_report >= 5:
+                if total:
+                    pct = (read / total) * 100
+                    print(f"  {_format_mb(read)} / {_format_mb(total)} ({pct:.1f}%)")
+                else:
+                    print(f"  {_format_mb(read)}")
+                last_report = now
+    partial.replace(destination)
+
+
+def download_urls(
+    urls: list[str],
+    output_dir: Path,
+    overwrite: bool,
+    *,
+    timeout_s: int = 60,
+    chunk_size: int = 1024 * 1024,
+) -> tuple[int, int, list[str]]:
     downloaded = 0
     skipped = 0
     failed: list[str] = []
@@ -155,15 +192,17 @@ def download_urls(urls: list[str], output_dir: Path, overwrite: bool) -> tuple[i
             print(f"skip existing {destination}")
             continue
 
+        partial = destination.with_suffix(f"{destination.suffix}.part")
+        if partial.exists() and not overwrite:
+            partial.unlink()
+
         print(f"download {url}")
         try:
-            request = Request(url, headers={"User-Agent": USER_AGENT})
-            with urlopen(request) as response, destination.open("wb") as output:
-                output.write(response.read())
+            _download_one(url, destination, timeout_s, chunk_size)
         except (HTTPError, URLError) as exc:
             failed.append(f"{url}: {exc}")
-            if destination.exists():
-                destination.unlink()
+            if partial.exists():
+                partial.unlink()
             continue
         downloaded += 1
 
@@ -178,6 +217,7 @@ def parse_args() -> argparse.Namespace:
     parser.add_argument("--index-url", default=META_CHM_V2_INDEX_URL)
     parser.add_argument("--urls-file", type=Path)
     parser.add_argument("--skip-url-check", action="store_true")
+    parser.add_argument("--timeout-s", default=60, type=int)
     parser.add_argument("--overwrite", action="store_true")
     return parser.parse_args()
 
@@ -199,7 +239,13 @@ def main() -> None:
     if not args.skip_url_check:
         validate_urls(urls)
 
-    downloaded, skipped, failed = download_urls(urls, args.output_dir, args.overwrite)
+    print(f"selected_tiles={len(urls)}")
+    downloaded, skipped, failed = download_urls(
+        urls,
+        args.output_dir,
+        args.overwrite,
+        timeout_s=args.timeout_s,
+    )
     print(f"downloaded={downloaded} skipped={skipped} failed={len(failed)}")
     if failed:
         for item in failed: