diff --git a/docker/Dockerfile.finn b/docker/Dockerfile.finn
index b3c669ec1097745bd30f650ca0b9dacda647c61d..dbafba247679895bcbaf385f0d33946c3f810945 100644
--- a/docker/Dockerfile.finn
+++ b/docker/Dockerfile.finn
@@ -84,7 +84,7 @@ RUN rm requirements.txt
 # extra Python package dependencies (for testing and interaction)
 RUN pip install pygments==2.4.1
 RUN pip install ipykernel==5.5.5
-RUN pip install jupyter==1.0.0
+RUN pip install jupyter==1.0.0 --ignore-installed
 RUN pip install markupsafe==2.0.1
 RUN pip install matplotlib==3.3.1 --ignore-installed
 RUN pip install pytest-dependency==0.5.1
diff --git a/requirements.txt b/requirements.txt
index 92601e7ecc5c41965d68770d9caef3473e6e5533..348b1afab9deca1547d40cb8d8c54a396befa65d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -9,6 +9,7 @@ onnxoptimizer
 onnxruntime==1.11.1
 pre-commit==2.9.2
 protobuf==3.20.2
+psutil==5.9.4
 pyscaffold==3.2.1
 scipy==1.5.2
 setupext-janitor>=1.1.2
diff --git a/src/finn/util/data_packing.py b/src/finn/util/data_packing.py
index 65478d2540b53443d3f74b44a22fde3defd8ca93..797dad32a2cfeb3e00e224f264d91b5ee0e9247b 100644
--- a/src/finn/util/data_packing.py
+++ b/src/finn/util/data_packing.py
@@ -265,7 +265,7 @@ def numpy_to_hls_code(
     # define a function to convert a single element into a C++ init string
     # a single element can be a hex string if we are using packing
     def elem2str(x):
-        if type(x) == str or type(x) == np.str_ or type(x) == np.str:
+        if type(x) == str or type(x) == np.str_:
             return '%s("%s", 16)' % (hls_dtype, x)
         elif type(x) == np.float32:
             if dtype.is_integer():