diff --git a/.pyproject_generation/pyproject_custom.toml b/.pyproject_generation/pyproject_custom.toml
index c7da1eb..395506f 100644
--- a/.pyproject_generation/pyproject_custom.toml
+++ b/.pyproject_generation/pyproject_custom.toml
@@ -1,6 +1,6 @@
 [project]
 name = "ghga_datasteward_kit"
-version = "4.1.1"
+version = "4.1.2"
 description = "GHGA Data Steward Kit - A utils package for GHGA data stewards."
 dependencies = [
     "crypt4gh >=1.6, <2",
diff --git a/pyproject.toml b/pyproject.toml
index f729057..43478fd 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -21,7 +21,7 @@ classifiers = [
     "Intended Audience :: Developers",
 ]
 name = "ghga_datasteward_kit"
-version = "4.1.1"
+version = "4.1.2"
 description = "GHGA Data Steward Kit - A utils package for GHGA data stewards."
 dependencies = [
     "crypt4gh >=1.6, <2",
diff --git a/src/ghga_datasteward_kit/s3_upload/config.py b/src/ghga_datasteward_kit/s3_upload/config.py
index 2abd798..227a14e 100644
--- a/src/ghga_datasteward_kit/s3_upload/config.py
+++ b/src/ghga_datasteward_kit/s3_upload/config.py
@@ -103,7 +103,7 @@ class LegacyConfig(S3ObjectStoragesConfig):
         default="https://data.ghga.de/.well-known",
         description="URL to the root of the WKVS API. Should start with https://.",
     )
-    client_timeout: NonNegativeInt = Field(
+    client_timeout: NonNegativeInt | None = Field(
         default=60, description="Timeout for client requests in seconds"
     )
     client_num_retries: NonNegativeInt = Field(
diff --git a/src/ghga_datasteward_kit/s3_upload/uploader.py b/src/ghga_datasteward_kit/s3_upload/uploader.py
index f18186e..bdc8501 100644
--- a/src/ghga_datasteward_kit/s3_upload/uploader.py
+++ b/src/ghga_datasteward_kit/s3_upload/uploader.py
@@ -162,7 +162,7 @@ async def send_part(self, part: bytes, part_number: int):
                 num_retries = HttpxClientConfig.num_retries
                 timeout = HttpxClientConfig.timeout
 
-                while True:
+                while True and timeout is not None:
                     LOG.info(
                         f"Attempting upload of part {part_number} ({len(part)} bytes) with a timeout of {
                             timeout} seconds."
diff --git a/src/ghga_datasteward_kit/s3_upload/utils.py b/src/ghga_datasteward_kit/s3_upload/utils.py
index 2531e2e..fa4b206 100644
--- a/src/ghga_datasteward_kit/s3_upload/utils.py
+++ b/src/ghga_datasteward_kit/s3_upload/utils.py
@@ -34,11 +34,11 @@
 class HttpxClientConfig:
     """Helper for user configurable httpx request parameters."""
 
-    num_retries: int = 5
-    timeout: int = 60
+    num_retries: int
+    timeout: int | None
 
     @classmethod
-    def configure(cls, num_retries: int, timeout: int):
+    def configure(cls, num_retries: int, timeout: int | None):
         """Set timeout in seconds"""
         cls.num_retries = num_retries
         cls.timeout = timeout
diff --git a/tests/test_s3_upload.py b/tests/test_s3_upload.py
index cf0956a..6c303ad 100644
--- a/tests/test_s3_upload.py
+++ b/tests/test_s3_upload.py
@@ -26,6 +26,7 @@
 from ghga_datasteward_kit.s3_upload import Config, LegacyConfig
 from ghga_datasteward_kit.s3_upload.entrypoint import async_main, legacy_async_main
 from ghga_datasteward_kit.s3_upload.utils import (
+    HttpxClientConfig,
     StorageCleaner,
     get_bucket_id,
     get_object_storage,
@@ -53,6 +54,8 @@ async def test_legacy_process(
     httpx_mock: HTTPXMock,
 ):
     """Test whole upload/download process for s3_upload script"""
+    HttpxClientConfig.configure(num_retries=5, timeout=60)
+
     with S3ContainerFixture() as container:
         s3_config = container.s3_config
 
@@ -84,6 +87,7 @@ async def test_legacy_process(
 @pytest.mark.asyncio
 async def test_process(config_fixture: Config, monkeypatch, httpx_mock: HTTPXMock):  # noqa: F811
     """Test whole upload/download process for s3_upload script"""
+    HttpxClientConfig.configure(num_retries=5, timeout=60)
 
     async def secret_exchange_dummy(
         *,