[tono1020]

Originally Posted by eschwartz

Quality Check is an alternative to mobi2mobi and works with both MOBI and AZW3.

Thanks eschwartz and 7hir7een!
I didn't know about Quality Check plugin. I tried it and it worked just fine, even for AZW3 format, so I will use it in future for syncing sideloaded AZW3 books.