If you've already got the Plugboard set up to re-map both title
then on a PRS505 it should be as simple as just selecting Books by Author
from the Sony main menu. The 505 seems to sort by author with the Plugboard-modified title_sort as a secondary sortkey.
There is also a second option, the 2 "special Collections", which work on both a PRS505 and PRSx50 (and hopefully a PRS600, but I don't know because I never owned one). The same Meta Plugboard is needed but you also need to go to Prefs - Plugins - Device Interface - Sony - Customize
and add the special Collections aba
to the define Collections box e.g. mine reads:
aba:%All by Author, abt:%All by Title, tags
These special Collections are accessed in the normal way, via Collections on the Sony main menu. The %char at the beginning of each special label ensures that they are listed on page 1 of the Collections list.
The reason these were provided is because on the PRSx50 models Sony has changed its standard by Author
list to sort by author without a secondary sortkey (or at least not a useful one).
If you've got spare time on your hands this thread
chronicles the 'Sony sort saga'