Normally I did the Extroot configuration, should it be enough ? What is weird is that once I unplug/plug the device it works as expected. For what is worth I just saw the device restart while it had factory settings and come back to my settings !
Here is the output of df -h and free -h:
root@GL-X750:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 10.8M 10.8M 0 100% /rom
tmpfs 60.3M 288.0K 60.1M 0% /tmp
/dev/sda1 14.5G 422.3M 13.4G 3% /overlay
overlayfs:/overlay 14.5G 422.3M 13.4G 3% /
tmpfs 512.0K 0 512.0K 0% /dev
/dev/sda1 14.5G 422.3M 13.4G 3% /mnt/sda1
/dev/mtdblock6 3.1M 3.0M 88.0K 97% /rwm
root@GL-X750:~# free -h
total used free shared buff/cache available
Mem: 123584 63112 39028 160 21444 28188
Swap: 262140 2312 259828
I dont think its a power problem as Power led is on, and then again the device it works as expected if I unplug/plug it again.