diff --git a/.github/scripts/run_test_apps.sh b/.github/scripts/run_test_apps.sh
index 8b0ec75a..264e3e16 100644
--- a/.github/scripts/run_test_apps.sh
+++ b/.github/scripts/run_test_apps.sh
@@ -11,7 +11,6 @@ xrun --xscope tests/unit/tests-unit.xe
 pytest ../tests/signal/TwoStageDecimator/ -vv
 
 # Filter design tests
-# TODO fix - https://github.com/xmos/lib_mic_array/issues/201
-# pytest ../tests/signal/FilterDesign/ -vv
+pytest ../tests/signal/FilterDesign/ -vv
 
 popd
diff --git a/script/filter_design/design_filter.py b/script/filter_design/design_filter.py
index 7f6115d5..0050f7b0 100644
--- a/script/filter_design/design_filter.py
+++ b/script/filter_design/design_filter.py
@@ -173,7 +173,8 @@ def design_3_stage(fs_0, decimations, ma_stages, stage_2: stage_params, stage_3:
     # add stopband filter points, design filter using windowed FIR method
     freqs = np.concatenate((freqs, np.array((stage_3.cutoff + stage_3.transition_bw/2, 0.5*fses[2]))))
     gains = np.concatenate((gains, np.zeros(2)))
-    coeff_3 = spsig.firwin2(stage_3.taps, freqs, gains, window=stage_3.fir_window, fs=fses[2])
+    gains_float64 = gains.astype(np.float64, copy=True)
+    coeff_3 = spsig.firwin2(stage_3.taps, freqs, gains_float64, window=stage_3.fir_window, fs=fses[2])
 
     if int_coeffs:
         coeff_2 = ft.float_coeffs_to_int32(coeff_2)