def _reset(self):
         self._hid_xfer(b"\x70\xAB\xCD\xEF", response=False)
+        self._hid.close()
         time.sleep(MCP2221_RESET_DELAY)
         start = time.monotonic()
         while time.monotonic() - start < 5:
         for _ in range(MCP2221_RETRY_MAX):
             status = self._i2c_status()
             if status[20] & MASK_ADDR_NACK:
-                raise RuntimeError("I2C slave address was NACK'd")
+                raise OSError("I2C slave address was NACK'd")
             usb_cmd_status = status[8]
             if usb_cmd_status == 0:
                 break
             # try a write
             try:
                 self.i2c_writeto(addr, b"\x00")
-            except RuntimeError:  # no reply!
+            except OSError:  # no reply!
+                # We got a NACK, which could be correct
                 continue
             # store if success
             found.append(addr)