When I built Mate I like the themes so I copy them when I built LXDE.
And I'm using FireFox ESR v 52.5.2
The first partition will have EFI and boot from the Porteus ISO. The second and third partition will have porteus but they will be rename jack1 and jack2. That the way I want it setup but if it won't work that way I will forger it and use 2 USB.