diff --git a/src/calibre/devices/cybookg3/driver.py b/src/calibre/devices/cybookg3/driver.py
index 20a7b259ee..6b5e5ff4ed 100644
--- a/src/calibre/devices/cybookg3/driver.py
+++ b/src/calibre/devices/cybookg3/driver.py
@@ -79,7 +79,7 @@ class CYBOOKG3(USBMS):
         return zip(paths, cycle([on_card]))
 
 
-class CYBOOK_OPUS(USBMS):
+class CYBOOK_OPUS(CYBOOKG3):
 
     name           = 'Cybook Opus Device Interface'
     gui_name       = 'Cybook Opus'