diff --git a/CMakeLists.txt b/CMakeLists.txt
index 219afccae..463417141 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -151,7 +151,7 @@ add_dependencies(_pynethack util) # For pm.h.
 
 # ttyrec converter library
 add_library(
-  converter SHARED ${CMAKE_CURRENT_SOURCE_DIR}/third_party/converter/converter.c
+  converter STATIC ${CMAKE_CURRENT_SOURCE_DIR}/third_party/converter/converter.c
                    ${CMAKE_CURRENT_SOURCE_DIR}/third_party/converter/stripgfx.c)
 target_include_directories(
   converter PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/third_party/libtmt
diff --git a/nle/tests/test_converter.py b/nle/tests/test_converter.py
index 75cad4595..587cd22be 100644
--- a/nle/tests/test_converter.py
+++ b/nle/tests/test_converter.py
@@ -72,7 +72,7 @@ def convert_n_times(n):
 
         memory_list = memory_usage((convert_n_times, (100,), {}))
         # After warmup the last few iterations should be constant memory
-        memory_array = np.array(memory_list[3:])
+        memory_array = np.array(memory_list[5:])
         memory_change = (memory_array / memory_array[0]) - 1
         assert max(memory_change) < 0.001  # 0.1 per cent