In my AR750 Creta
- Save backup User config
- Update Firmware resetting everything 3.201-402 (beta6)
- Install Luci just right after updating
I had a 512Mb USB in it and also a 64Gb SD
I made /overlay in Luci>System>Mount Points
Add
Select SD or USB Flash, in my case USB.
/overlay
Reboot.
Easy after few tries.
Import User Config
Bye