diff --git a/rednose_repo b/rednose_repo
index 7663289f1e..3a6f937ad1 160000
--- a/rednose_repo
+++ b/rednose_repo
@@ -1 +1 @@
-Subproject commit 7663289f1e68860f53dc34337ef080dde69a2586
+Subproject commit 3a6f937ad1bb234dca7b0b2052faabdd58f3e085
diff --git a/selfdrive/locationd/models/car_kf.py b/selfdrive/locationd/models/car_kf.py
index fe7d2e650b..3faf4f8d4e 100755
--- a/selfdrive/locationd/models/car_kf.py
+++ b/selfdrive/locationd/models/car_kf.py
@@ -15,7 +15,7 @@ if __name__ == '__main__':  # Generating sympy
   import sympy as sp
   from rednose.helpers.ekf_sym import gen_code
 else:
-  from rednose.helpers.ekf_sym_pyx import EKF_sym  # pylint: disable=no-name-in-module, import-error
+  from rednose.helpers.ekf_sym_pyx import EKF_sym_pyx  # pylint: disable=no-name-in-module, import-error
 
 
 i = 0
@@ -171,7 +171,7 @@ class CarKalman(KalmanFilter):
     if P_initial is not None:
       self.P_initial = P_initial
     # init filter
-    self.filter = EKF_sym(generated_dir, self.name, self.Q, self.initial_x, self.P_initial, dim_state, dim_state_err, global_vars=self.global_vars, logger=cloudlog)
+    self.filter = EKF_sym_pyx(generated_dir, self.name, self.Q, self.initial_x, self.P_initial, dim_state, dim_state_err, global_vars=self.global_vars, logger=cloudlog)
 
 
 if __name__ == "__main__":
diff --git a/selfdrive/locationd/models/gnss_kf.py b/selfdrive/locationd/models/gnss_kf.py
index ce0ff84dc2..5c9cb4b3d1 100755
--- a/selfdrive/locationd/models/gnss_kf.py
+++ b/selfdrive/locationd/models/gnss_kf.py
@@ -3,12 +3,17 @@ import sys
 from typing import List
 
 import numpy as np
-import sympy as sp
 
-from rednose.helpers.ekf_sym import EKF_sym, gen_code
 from selfdrive.locationd.models.constants import ObservationKind
 from selfdrive.locationd.models.gnss_helpers import parse_pr, parse_prr
 
+if __name__ == '__main__':  # Generating sympy
+  import sympy as sp
+  from rednose.helpers.ekf_sym import gen_code
+else:
+  from rednose.helpers.ekf_sym_pyx import EKF_sym_pyx  # pylint: disable=no-name-in-module,import-error
+  from rednose.helpers.ekf_sym import EKF_sym  # pylint: disable=no-name-in-module,import-error
+
 
 class States():
   ECEF_POS = slice(0, 3)  # x, y and z in ECEF in meters
@@ -115,12 +120,13 @@ class GNSSKalman():
 
     gen_code(generated_dir, name, f_sym, dt, state_sym, obs_eqs, dim_state, dim_state, maha_test_kinds=maha_test_kinds)
 
-  def __init__(self, generated_dir):
+  def __init__(self, generated_dir, cython=False):
     self.dim_state = self.x_initial.shape[0]
 
     # init filter
-    self.filter = EKF_sym(generated_dir, self.name, self.Q, self.x_initial, self.P_initial, self.dim_state,
-                          self.dim_state, maha_test_kinds=self.maha_test_kinds)
+    filter_cls = EKF_sym_pyx if cython else EKF_sym
+    self.filter = filter_cls(generated_dir, self.name, self.Q, self.x_initial, self.P_initial, self.dim_state,
+                             self.dim_state, maha_test_kinds=self.maha_test_kinds)
     self.init_state(GNSSKalman.x_initial, covs=GNSSKalman.P_initial)
 
   @property