[izprtxqkft]

When you used adb connection were you able to gain R/W of the new USB drive? If I formatted to internal storage I did not have any write access..

that's why i listed it as a caveat at the end of the instructions, i don't have any user friendly way of getting existing data to the new folder and i never pursued it because the user i was providing instructions for never got that far
i will have a think on it and try a few things see if i can come up with something

edit:

is the backup addon still functional? that could be an option if so https://kodi.wiki/view/Add-on:Backup

edit2:

to answer myself, yes the backup addon is still perfectly functional
so the amended instructions to keep existing data would be

1. install the backup addon
   
2. perform a backup and use a location on the sdcard (compression disabled, skip thumbnails/fanart)
   
3. then create the env file to redirect the userdata folder
   
4. restart kodi so that it's using the new location
   
5. install the backup addon again in the new kodi
   
6. restore the userdata backup (ensure you select items to restore, they should be highlighted in green)
   
7. restart kodi
   

then everything should be copacetic, im not using external at the moment but i did just test the addon's backup/restore functionality and it's 100% good and since it's all being done from kodi's user id there should be no issues

[blazin912]

OK I'll give that a shot I'll let you know how it goes.

[b1ggles]

I use the standard backup addon to do a full backup but also export the library as that doesn't always come back properly. Backup to a network share, delete Kodi, reinstall to external storage (will do this by default after adding external through the FireTV menu), set network share on fresh install, install backup addon, restore, import library...away you go.

Done it multiple times when swapping to different nightlies, easy peasy after you get over the initial finger crossing anxiety.