I figured it out, having a µSD card in the Kobo during startup breaks the loading.
Once nickel loads, you can put the µSD card back in (even before loading the Library/plugin) and everything works fine. This occurred when I had some epubs & pdfs on the card and also appeared when I didn't have any indexed files on the card, just some ignored fonts & Calibre files. (I don't think content is the issue.)
I could send you the version info, but I'm not sure it really matters. If it's any help, I saw this issue with all old versions I tested (back to
post #11) Also, even with the card breaking full loading, the plugin
would create the .ini file. So something after that might be a good starting point. (Disclosure: I don't actually know anything.)