Slight detection changes for Cybooks.

src/calibre/customize/builtins.py

@@ -455,6 +455,7 @@ plugins += [
     TCROutput,
     TXTOutput,
 ]
+# Order here matters. The first matched device is the one used.
 plugins += [
     HANLINV3,
     HANLINV5,

src/calibre/devices/cybookg3/driver.py

@@ -70,8 +70,6 @@ class CYBOOK_OPUS(CYBOOKG3):
     author         = 'John Schember'
     supported_platforms = ['windows', 'osx', 'linux']
 
-    FORMATS = ['epub', 'pdf', 'txt']
-
     VENDOR_ID   = [0x0bda]
     PRODUCT_ID  = [0x0703]
     BCD         = [0x110]
@@ -90,5 +88,5 @@ class CYBOOK_OPUS(CYBOOKG3):
     @classmethod
     def can_handle(cls, device_info, debug=False):
         if isunix:
-            return device_info[3] == 'Bookeen'
+            return device_info[3] == 'Bookeen' and device_info[4] == 'Cybook Opus'
         return True