diff --git a/pkgs/development/python-modules/brax/default.nix b/pkgs/development/python-modules/brax/default.nix
index 849d44c7fab2..dbde33329245 100644
--- a/pkgs/development/python-modules/brax/default.nix
+++ b/pkgs/development/python-modules/brax/default.nix
@@ -54,13 +54,21 @@ buildPythonPackage (finalAttrs: {
     ./dont-use-device_put_replicated-compat.patch
   ];
 
-  # TypeError: clip() got an unexpected keyword argument 'a_min'
-  postPatch = ''
-    substituteInPlace brax/fluid.py \
-      --replace-fail \
-        "box = 6.0 * jp.clip(jp.sum(diag_inertia_v, axis=-1), a_min=1e-12)" \
-        "box = 6.0 * jp.clip(jp.sum(diag_inertia_v, axis=-1), min=1e-12)"
-  '';
+  postPatch =
+    # TypeError: clip() got an unexpected keyword argument 'a_min'
+    ''
+      substituteInPlace brax/fluid.py \
+        --replace-fail \
+          "box = 6.0 * jp.clip(jp.sum(diag_inertia_v, axis=-1), a_min=1e-12)" \
+          "box = 6.0 * jp.clip(jp.sum(diag_inertia_v, axis=-1), min=1e-12)"
+    ''
+    # mujoco >= 3.10 changed mj_fullM's signature from (m, dst, qM) to (m, d, dst).
+    + ''
+      substituteInPlace brax/generalized/mass_test.py \
+        --replace-fail \
+          "mujoco.mj_fullM(model, mj_mass_mx, mj_next.qM)" \
+          "mujoco.mj_fullM(model, mj_next, mj_mass_mx)"
+    '';
 
   build-system = [
     hatchling