I think Porteus should develop an installation procedure for these machines (and newer with uefi), something like:
1) inserting a new usb (factory formatted),
2)downloading iso2usb, detecting eventual uefi,
3)rebooting iso, shrinking fat32 parition of usb and formatting partition in posix format (ext4),
4)installing Porteus in Partition 2,
5)deleting contents of Partition 1 and eventually installing UEFI.
I guess Jay is working in something like that, I know my friends

Regards!