Calibre won’t see my Glo HD.

[b3ta]

I haven’t used this Glo for about a year. I managed to update to the latest (4.35) yesterday. I’m using Calibre 6.11 with macOS Catalina. If I manage connect to it successfully, It doesn’t appear in Calibre - all I see is three books that I synced at some point in the past (but not the rest of the books on the Kobo, which I must have synced at some point). I say ‘successfully’ because most times when I connect it, it flashes between the ‘computer connect’ screen and the main screen. This doesn’t usually happen when I connect it to the mains to charge, but does sometimes. I tried to connect to wifi (successfully) and access my Pocket account, which surprised me as in the past it never worked on wifi (although it saw the network and accepted the password). Can I sync books over wifi? I tried to reset it using the little hole on the bottom, but it didn’t seem to help. Anyone know what’s happening/wrong?