diff --git a/test_runner/regress/test_ondemand_download.py b/test_runner/regress/test_ondemand_download.py
index 09657470b6..5ee94de32d 100644
--- a/test_runner/regress/test_ondemand_download.py
+++ b/test_runner/regress/test_ondemand_download.py
@@ -218,6 +218,9 @@ def test_ondemand_download_timetravel(
     log.info(filled_size)
     assert filled_current_physical == filled_size, "we don't yet do layer eviction"
 
+    # Wait until generated image layers are uploaded to S3
+    time.sleep(3)
+
     env.pageserver.stop()
 
     # remove all the layer files
diff --git a/test_runner/regress/test_tenants_with_remote_storage.py b/test_runner/regress/test_tenants_with_remote_storage.py
index 6da6a4d446..769bc10280 100644
--- a/test_runner/regress/test_tenants_with_remote_storage.py
+++ b/test_runner/regress/test_tenants_with_remote_storage.py
@@ -280,6 +280,7 @@ def test_tenant_upgrades_index_json_from_v0(
 
         timeline_file.seek(0)
         json.dump(v0_index_part, timeline_file)
+        timeline_file.truncate(timeline_file.tell())
 
     env.pageserver.start()
     pageserver_http = env.pageserver.http_client()