diff --git a/src/pystencils/backend/platforms/cuda.py b/src/pystencils/backend/platforms/cuda.py
index 95480de93e72698dbe2b28c997bd096be6b383e5..bf5b91b8228029cdcc9305be64a3879f3412b97d 100644
--- a/src/pystencils/backend/platforms/cuda.py
+++ b/src/pystencils/backend/platforms/cuda.py
@@ -156,7 +156,7 @@ class CudaPlatform(GenericGpu):
                 assert isinstance(symbol_expr, PsSymbolExpr) and isinstance(symbol_expr.dtype, PsScalarType)
 
                 call.function = CFunction(f"atomic{op.name}", [ptr_expr.dtype, symbol_expr.dtype], PsCustomType("void"))
-                call.args = [ptr_expr, symbol_expr]
+                call.args = (ptr_expr, symbol_expr)
 
                 if not isinstance(symbol_expr.dtype, PsIeeeFloatType) or symbol_expr.dtype.width not in (32, 64):
                     NotImplementedError("atomicMul is only available for float32/64 datatypes")
diff --git a/src/pystencils/backend/platforms/sycl.py b/src/pystencils/backend/platforms/sycl.py
index dd38aeb48b1089c06f2c6a2d4c6fa822ccacf727..2ea2934f387b34b475360481cb2cc560cf4f3888 100644
--- a/src/pystencils/backend/platforms/sycl.py
+++ b/src/pystencils/backend/platforms/sycl.py
@@ -112,7 +112,9 @@ class SyclPlatform(GenericGpu):
     def unfold_function(
         self, call: PsCall
     ) -> PsAstNode:
-        pass
+        raise MaterializationError(
+            f"No implementation available for function {call.function.name}"
+        )
 
     def _prepend_dense_translation(
         self, body: PsBlock, ispace: FullIterationSpace