diff --git a/dev/runcpu.sh b/dev/runcpu.sh
index 469e51d..ffacefa 100755
--- a/dev/runcpu.sh
+++ b/dev/runcpu.sh
@@ -22,13 +22,6 @@ fi
 curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
 source "$HOME/.cargo/env"
 uv run maturin develop --release --manifest-path rustbpe/Cargo.toml
-EVAL_BUNDLE_URL=https://karpathy-public.s3.us-west-2.amazonaws.com/eval_bundle.zip
-if [ ! -d "$NANOCHAT_BASE_DIR/eval_bundle" ]; then
-    curl -L -o eval_bundle.zip $EVAL_BUNDLE_URL
-    unzip -q eval_bundle.zip
-    rm eval_bundle.zip
-    mv eval_bundle $NANOCHAT_BASE_DIR
-fi
 
 # wipe the report
 python -m nanochat.report reset
diff --git a/nanochat/common.py b/nanochat/common.py
index a5a6d2e..8272378 100644
--- a/nanochat/common.py
+++ b/nanochat/common.py
@@ -58,7 +58,7 @@ def get_base_dir():
     os.makedirs(nanochat_dir, exist_ok=True)
     return nanochat_dir
 
-def download_file_with_lock(url, filename):
+def download_file_with_lock(url, filename, postprocess_fn=None):
     """
     Downloads a file from a URL to a local path in the base directory.
     Uses a lock file to prevent concurrent downloads among multiple ranks.
@@ -76,18 +76,24 @@ def download_file_with_lock(url, filename):
         # All other ranks block until it is released
         fcntl.flock(lock_file.fileno(), fcntl.LOCK_EX)
 
+        # Recheck after acquiring lock (another process may have downloaded it)
         if os.path.exists(file_path):
             return file_path
 
+        # Download the content as bytes
         print(f"Downloading {url}...")
         with urllib.request.urlopen(url) as response:
-            content = response.read().decode('utf-8')
+            content = response.read() # bytes
 
-        with open(file_path, 'w') as f:
+        # Write to local file
+        with open(file_path, 'wb') as f:
             f.write(content)
-
         print(f"Downloaded to {file_path}")
 
+        # Run the postprocess function if provided
+        if postprocess_fn is not None:
+            postprocess_fn(file_path)
+
     # Clean up the lock file after the lock is released
     try:
         os.remove(lock_path)
diff --git a/run1000.sh b/run1000.sh
index 6f454e0..e0bc4c4 100644
--- a/run1000.sh
+++ b/run1000.sh
@@ -19,13 +19,6 @@ python -m nanochat.report reset
 curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
 source "$HOME/.cargo/env"
 uv run maturin develop --release --manifest-path rustbpe/Cargo.toml
-EVAL_BUNDLE_URL=https://karpathy-public.s3.us-west-2.amazonaws.com/eval_bundle.zip
-if [ ! -d "$NANOCHAT_BASE_DIR/eval_bundle" ]; then
-    curl -L -o eval_bundle.zip $EVAL_BUNDLE_URL
-    unzip -q eval_bundle.zip
-    rm eval_bundle.zip
-    mv eval_bundle $NANOCHAT_BASE_DIR
-fi
 curl -L -o $NANOCHAT_BASE_DIR/identity_conversations.jsonl https://karpathy-public.s3.us-west-2.amazonaws.com/identity_conversations.jsonl
 
 # train tokenizer on ~4B characters and kick off download of the rest for pretraining
diff --git a/scripts/base_eval.py b/scripts/base_eval.py
index c488c8a..21f7bac 100644
--- a/scripts/base_eval.py
+++ b/scripts/base_eval.py
@@ -2,10 +2,10 @@
 Evaluate the CORE metric for a given model.
 
 Run on a single GPU:
-python base_eval.py
+python -m scripts.base_eval
 
 Run with torchrun on e.g. 8 GPUs:
-torchrun --nproc_per_node=8 base_eval.py
+torchrun --nproc_per_node=8 -m scripts.base_eval
 
 The script will print the CORE metric to the console.
 """
@@ -13,13 +13,16 @@ import os
 import csv
 import time
 import json
-import random
 import yaml
+import shutil
+import random
+import zipfile
+import tempfile
 from contextlib import nullcontext
 
 import torch
 
-from nanochat.common import compute_init, compute_cleanup, print0, get_base_dir, autodetect_device_type
+from nanochat.common import compute_init, compute_cleanup, print0, get_base_dir, autodetect_device_type, download_file_with_lock
 from nanochat.tokenizer import HuggingFaceTokenizer
 from nanochat.checkpoint_manager import load_model
 from nanochat.core_eval import evaluate_task
@@ -27,6 +30,21 @@ from nanochat.core_eval import evaluate_task
 # -----------------------------------------------------------------------------
 # nanochat specific function dealing with I/O etc.
 
+# ~162MB of data needed to evaluate the CORE metric
+EVAL_BUNDLE_URL = "https://karpathy-public.s3.us-west-2.amazonaws.com/eval_bundle.zip"
+
+def place_eval_bundle(file_path):
+    # here file_path is the path to the eval_bundle.zip file
+    # we need to unzip it and place it in the base directory
+    base_dir = get_base_dir()
+    eval_bundle_dir = os.path.join(base_dir, "eval_bundle")
+    with tempfile.TemporaryDirectory() as tmpdir:
+        with zipfile.ZipFile(file_path, 'r') as zip_ref:
+            zip_ref.extractall(tmpdir)
+        extracted_bundle_dir = os.path.join(tmpdir, "eval_bundle")
+        shutil.move(extracted_bundle_dir, eval_bundle_dir)
+    print0(f"Placed eval_bundle directory at {eval_bundle_dir}")
+
 def evaluate_model(model, tokenizer, device, max_per_task=-1):
     """
     Evaluate a base model on the CORE benchmark.
@@ -35,6 +53,9 @@ def evaluate_model(model, tokenizer, device, max_per_task=-1):
     # Load config and task metadata
     base_dir = get_base_dir()
     eval_bundle_dir = os.path.join(base_dir, "eval_bundle")
+    # Download the eval bundle to disk (and unzip if needed)
+    if not os.path.exists(eval_bundle_dir):
+        download_file_with_lock(EVAL_BUNDLE_URL, "eval_bundle.zip", postprocess_fn=place_eval_bundle)
     config_path = os.path.join(eval_bundle_dir, "core.yaml")
     data_base_path = os.path.join(eval_bundle_dir, "eval_data")
     eval_meta_data = os.path.join(eval_bundle_dir, "eval_meta_data.csv")
diff --git a/speedrun.sh b/speedrun.sh
index 35dd39e..32c8870 100644
--- a/speedrun.sh
+++ b/speedrun.sh
@@ -73,15 +73,6 @@ python -m scripts.tok_eval
 # -----------------------------------------------------------------------------
 # Base model (pretraining)
 
-# Download the eval_bundle from s3 to evaluate CORE metric during training (~162MB)
-EVAL_BUNDLE_URL=https://karpathy-public.s3.us-west-2.amazonaws.com/eval_bundle.zip
-if [ ! -d "$NANOCHAT_BASE_DIR/eval_bundle" ]; then
-    curl -L -o eval_bundle.zip $EVAL_BUNDLE_URL
-    unzip -q eval_bundle.zip
-    rm eval_bundle.zip
-    mv eval_bundle $NANOCHAT_BASE_DIR
-fi
-
 # The d20 model is 561M parameters.
 # Chinchilla says #tokens = 20X #params, so we need 561e6 * 20 = 11.2B tokens.
 # Assume our tokenizer is 4.8 chars/token, this is 11.2B * 4.8 ~= 54B chars.