Tolino Vision 6: problem with transfering books to device (books get deleted)

So, a few weeks ago, I was having trouble, and asked over here (https://www.mobileread.com/forums/sh...d.php?t=346774) because I kept getting error messages. I still do, and have to unplug the device every few books when transferring, which is annoying a little, but manageable.

I'm not sure this has to do with the most current update (5.43 on Linux Mint), but now in this process of constantly unplugging and plugging the device back in, calibre appears to not find all the books it just transferred. The device had all of them on it already, but in the process of calibre recognizing the books on the device, some of them get deleted on the device.

As an example:
So I have a bunch of the Drizzt books, by R.A. Salvatore and am trying to transfer them.
I manage to transfer something like 5-10 books in that series before I get the error message (see other thread) and have to un/re-connect the reader. These 10 books are available on the device. Then I reconnect the reader and Calibre tries to recognize the books, but doesn't see that the books are already there, or only some of them.

And in this process of recognizing, some of those books get deleted off of the device, so I have to do the transfer over again, making me go in circles.

I can't really tell what's going on, so does anyone have any ideas?
Thanks!