diff --git a/tinygrad/tensor.py b/tinygrad/tensor.py
index 53a7790a62..307c1ae17b 100644
--- a/tinygrad/tensor.py
+++ b/tinygrad/tensor.py
@@ -282,7 +282,7 @@ class Tensor(MathTrait):
     # TODO: this is a hack for writing to DISK. remove with working assign
     if isinstance(self.device, str) and self.device.startswith("DISK"):
       if x.__class__ is not Tensor: x = Tensor(x, device="CPU", dtype=self.dtype)
-      cast(Buffer, self.contiguous().realize().uop.base.buffer).ensure_allocated().copyin(x._data())
+      self._buffer().copyin(x._data())
       return self
     if x.__class__ is not Tensor: x = Tensor(x, device=self.device, dtype=self.dtype)
     if self.uop is x.uop: return self  # a self assign is a NOOP
@@ -299,7 +299,10 @@ class Tensor(MathTrait):
     """
     return Tensor(self.uop.detach(), device=self.device, requires_grad=False)
 
-  def _buffer(self) -> Buffer: return cast(Buffer, self.cast(self.dtype.base).contiguous().to("CPU").realize().uop.base.buffer)
+  def _buffer(self) -> Buffer:
+    x = self.cast(self.dtype.base).contiguous()
+    if isinstance(self.device, tuple): x = x.to("CPU")
+    return cast(Buffer, x.realize().uop.base.buffer).ensure_allocated()
   def _data(self) -> memoryview: return self._buffer().as_buffer()
 
   def data(self) -> memoryview: