Wndr 4700 packages install change from root to hdd

HI GUYS

Need help. I just flash LEDE on my WNDR 4700. I just using this for now as switch to extend my network.

i wanted to switch the storage of package manager install to HDD location.

for now it says only

i need to change in the config from Root ie flash storage being limited to 22MB or 30MB for netgear .

Here is the config tab look alike.