Have you tried typing ifconfig to see what physical NICs you have in the LEDE VM (and the NiC cards' names)???
In addition....the command is "UCI SET" NOT "UCI ADD."
Have you tried typing ifconfig to see what physical NICs you have in the LEDE VM (and the NiC cards' names)???
In addition....the command is "UCI SET" NOT "UCI ADD."
ifconfig shows no NICs.
I think part of the problem is that when trying to create any files the drive shows as full, although I can't determine why that would be.
I followed the instructions below and everything worked as expected.
I decided to better assist by just creating a VM:
VBoxManage converdd lede-17.01.4-x86-generic-combined-ext4.img.gz lede.vdi
Glad you got it working!
Consider editing the title and adding "[Solved]."