diff --git a/backends/arm/_passes/decompose_masked_fill_pass.py b/backends/arm/_passes/decompose_masked_fill_pass.py
index 09a3492a0c6..49a4bbb9b4b 100644
--- a/backends/arm/_passes/decompose_masked_fill_pass.py
+++ b/backends/arm/_passes/decompose_masked_fill_pass.py
@@ -17,7 +17,7 @@
 
 
 edge_ops = (exir_ops.edge.aten.masked_fill.Scalar,)
-aten_ops = (torch.ops.aten.masked_fill.Scalar,)
+aten_ops = (torch.ops.aten.masked_fill.Scalar, torch.ops.aten.masked_fill_.Scalar)
 
 
 def _get_decomposition(op) -> tuple:
@@ -26,7 +26,7 @@ def _get_decomposition(op) -> tuple:
             exir_ops.edge.aten.where.self,
             exir_ops.edge.aten.full_like.default,
         )
-    if op in aten_ops:
+    elif op in aten_ops:
         return (
             torch.ops.aten.where.self,
             torch.ops.aten.full_like.default,
@@ -44,7 +44,7 @@ class DecomposeMaskedFillPass(ArmPass):
     _passes_required_after: Set[Type[ExportPass]] = {ConvertFullLikeToFullPass}
 
     def call_operator(self, op, args, kwargs, meta, updated=False):
-        if op not in (edge_ops + aten_ops):
+        if op not in (*aten_ops, *edge_ops):
             return super().call_operator(op, args, kwargs, meta, updated)
 
         x, mask, scalar = args
diff --git a/backends/arm/test/models/stable_diffusion/test_CLIPTextModelWithProjection.py b/backends/arm/test/models/stable_diffusion/test_CLIPTextModelWithProjection.py
index d41007e1e76..938732fa91a 100644
--- a/backends/arm/test/models/stable_diffusion/test_CLIPTextModelWithProjection.py
+++ b/backends/arm/test/models/stable_diffusion/test_CLIPTextModelWithProjection.py
@@ -45,9 +45,7 @@ class TestCLIPTextModelWithProjection:
         "executorch_exir_dialects_edge__ops_aten_index_select_default": 1,
         "executorch_exir_dialects_edge__ops_aten_slice_copy_Tensor": 1,
         "executorch_exir_dialects_edge__ops_aten_view_copy_default": 1,
-        "executorch_exir_dialects_edge__ops_aten_where_self": 1,
         "executorch_exir_dialects_edge__ops_dim_order_ops__to_dim_order_copy_default": 2,
-        "torch.ops.aten.scalar_tensor.default": 1,
         "torch.ops.higher_order.executorch_call_delegate": 2,
     }
 
diff --git a/backends/arm/test/models/test_conformer.py b/backends/arm/test/models/test_conformer.py
index 85ac2733e70..e04d8bd44a5 100644
--- a/backends/arm/test/models/test_conformer.py
+++ b/backends/arm/test/models/test_conformer.py
@@ -72,15 +72,8 @@ def test_conformer_tosa_INT():
         aten_op=[],
         exir_op=[],
         use_to_edge_transform_and_lower=True,
-    )
-    pipeline.pop_stage("check_count.exir")
-    pipeline.change_args(
-        "run_method_and_compare_outputs",
-        get_test_inputs(
-            TestConformer.dim, TestConformer.lengths, TestConformer.num_examples
-        ),
-        rtol=TestConformer.rtol,
         atol=TestConformer.atol,
+        rtol=TestConformer.rtol,
     )
     pipeline.run()
 
@@ -93,38 +86,26 @@ def test_conformer_u55_INT():
     pipeline = EthosU55PipelineINT[input_t](
         TestConformer.conformer,
         TestConformer.model_example_inputs,
-        aten_ops=TestConformer.aten_ops,
+        aten_ops=[],
         exir_ops=[],
         use_to_edge_transform_and_lower=True,
+        atol=TestConformer.atol,
+        rtol=TestConformer.rtol,
     )
-    pipeline.change_args(
-        "run_method_and_compare_outputs",
-        get_test_inputs(
-            TestConformer.dim, TestConformer.lengths, TestConformer.num_examples
-        ),
-        rtol=1.0,
-        atol=5.0,
-    )
+    pipeline.pop_stage("check_count.exir")
     pipeline.run()
 
 
 @common.XfailIfNoCorstone320
-@pytest.mark.xfail(reason="All IO needs to have the same data type (MLETORCH-635)")
 def test_conformer_u85_INT():
     pipeline = EthosU85PipelineINT[input_t](
         TestConformer.conformer,
         TestConformer.model_example_inputs,
-        aten_ops=TestConformer.aten_ops,
+        aten_ops=[],
         exir_ops=[],
         use_to_edge_transform_and_lower=True,
-    )
-    pipeline.change_args(
-        "run_method_and_compare_outputs",
-        get_test_inputs(
-            TestConformer.dim, TestConformer.lengths, TestConformer.num_examples
-        ),
-        rtol=1.0,
-        atol=5.0,
+        atol=TestConformer.atol,
+        rtol=TestConformer.rtol,
     )
     pipeline.run()
 
@@ -137,16 +118,9 @@ def test_conformer_vgf_quant():
         aten_op=[],
         exir_op=[],
         use_to_edge_transform_and_lower=True,
-        quantize=True,
-    )
-    pipeline.pop_stage("check_count.exir")
-    pipeline.change_args(
-        "run_method_and_compare_outputs",
-        get_test_inputs(
-            TestConformer.dim, TestConformer.lengths, TestConformer.num_examples
-        ),
-        rtol=TestConformer.rtol,
         atol=TestConformer.atol,
+        rtol=TestConformer.rtol,
+        quantize=True,
     )
     pipeline.run()