I installed firmware 2.4.0 (because I'm an impatient stupidhead). At first, I thought this-google-drive-tool-that-needs-a-name needed to be reinstalled after firmware upgrade because the books on the virtual SD weren't visible even after restart.
So I reinstalled this-google-drive-tool-that-needs-a-name, and still nothing.
So I synced: tadaaa there the Google Drive books are, back on my home screen
WITHOUT processing btw so they were there all along, just not visible. Plugging in USB and unplugging: books are still there.
So so far, this-google-drive-tool-that-needs-a-name seems to work with 2.4.0.
Would be nice if there's a way to have the virtual SD always "switch on" without needing a sync though.