Sony Reader PRS-T1 - Communication error

[David Rodriguez]

Using calibre 5.3 (also happens in 5.2, not tested in other 5.x versions), when connecting my old Sony PRS-T1 Reader, an error dialog appears indicating "Communication error with the device" (In spanish: "Error en la comunicación con el dispositivo") with the following stack trace:

calibre, version 5.3.0
ERROR: Error: Error en la comunicación con el dispositivo

'>' not supported between instances of 'NoneType' and 'NoneType'

Traceback (most recent call last):
  File "calibre\gui2\device.py", line 89, in run
  File "calibre\gui2\device.py", line 512, in _books
  File "calibre\devices\prst1\driver.py", line 166, in books
  File "calibre\devices\usbms\driver.py", line 306, in books
  File "calibre\devices\prst1\driver.py", line 249, in sync_booklists
  File "calibre\devices\prst1\driver.py", line 276, in update_device_database
  File "calibre\devices\usbms\books.py", line 308, in get_collections
  File "calibre\devices\usbms\books.py", line 27, in none_cmp
  File "polyglot\builtins.py", line 114, in cmp
TypeError: '>' not supported between instances of 'NoneType' and 'NoneType'

The steps to reproduce are simple: Just open Calibre, connect the PRS-T1 by usb, and the error appears few seconds after (I suppose Calibre is getting the reader contents, and fails here).

I get this error in this platform:
- PC: Windows 10 64 bit
- E-Reader: Sony PRS-T1
- Calibre version: 5.3 (Windows 64-bit). I get the same error in 5.2 (not tested in other 5.x versions)

WORKAROUND:
calibre 4.23 64-bit is working fine. Meanwhile I've uninstalled 5.3, and returned to 4.23

Let me know if you need more data from my side.