[Tinwarble]

How can I copy the .spmc (or .kodi) folder from one Shield to another? Just tried using ESFileExplorer to do this to a network share, it shows copy failed. Same issue trying to copy to an attached USB stick. Tried the Backup Kodi program add-on, and same issue trying to copy out. How do you do this?

First, don't use ES File Explorer, not only does it cause issues on the Shield, it's just bloatware. If you need a file explorer use X-Plore or Total Commander.

Also, you can NOT write to network mounted shares (Android limitation), but you should have no issues writing to network shares directly, you shouldn't even need to write to it as a mounted share. And for USB drives you can only write to the apps folder on the drive (by default, also a Android limitation) without the app asking permission first, like Total Commander.

Have you mounted these shares? There appears to be an issue where you cannot write to mounted network shares.

It's not a "issue" it's an Android limitation.