[chaley]

The attached driver file lets you choose different destination directories for main memory and for the card. It does not change where calibre.metadata goes (the root), so if that exception is still being thrown, this driver will not help. And as you have already set up the customization to put books in MyBooks on both the main memory and the card, you probably won't see any benefit from this driver.

But should you wish to try it, the driver will go in
/home/kovid/build/calibre/src/calibre/devices/hanlin/driver.py
If there is an existing driver file by that name, save it somewhere. You must remember to delete this patched driver when next you update calibre.

Edit: note that the changes in this driver have not yet been approved for general release.