diff --git a/requirements.txt b/requirements.txt
index de3239cbdd42..6313cecee578 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -12,7 +12,7 @@ scipy>=1.4.1
 torch>=1.7.0
 torchvision>=0.8.1
 tqdm>=4.64.0
-protobuf<4.21.3  # https://github.com/ultralytics/yolov5/issues/8012
+protobuf<=3.20.1  # https://github.com/ultralytics/yolov5/issues/8012
 
 # Logging -------------------------------------
 tensorboard>=2.4.1