I found another way to run on virtual box thats really easy.
Boot into nemesis and go to gparted. Create partition table GPT and then make a fat32 500MB. go to flags and select boot and esp. Then create a second partition as ext4 with the rest of the drive. Go to nemesis installer and install it to the second drive. Then copy all the folders except config and porteus to the first partition.
create a folder called changes on sda2
then on the first partiton go to /boot/syslinux/porteus.cfg
Add the changes folder and the porteus location
APPEND changes=/mnt/sda2/changes From=/mnt/sda2/porteus
Lastly in virtual box select enable EFI on the first setting page.
Then you can boot nemesis and the bootloader wont get touched like MBR (Only applies to .vdi and virtual box)
See my post about increasing the video memory to 256mb at the bottom
[HOWTO] Setup VirtualBox Guest Addition Module, Shared Folders and Clip-board (Post by dreadbird #101607)
As a side note
My take on MBR and GPT. One or the other is easy a few clicks in gparted and done. What is not so straight foward is grub2. I played around with it by having debian install grub2 to a .vdi. Then I edited the config to boot porteus MBR. Im sure if I played around with it enough I could do GPT as well. But you have to ask yourself should you even bother learning all that? Syntax and commands that are not straight foward. An implementation that doesnt recognize porteus as an os?
Im my opinion any program that breaks at the slightest configuration misalignment is laughable. you make a program you make a guide to use it. A guide should not contain useless commands and if a command is listed explain what it does. This is why the arch wiki to me is useless. Therefor let the distributions like ubuntu and debian configure it for you. Im thankful porteus doesnt use grub2 because it may be great in the eyes of a software engineer or programmer but is not useful for the user.
Lets show the stanza or boot entry for grub bootloader if you were to use one
You would have two seperate harddrives not mixing MBR or gpt
Add these to custom 40 .cfg ( or convert them to actual menu entry with grub customizer)
#this boots porteus MBR Tested this works
menuentry "Porteus5.01" {
set root='(hd0,1)'
search --no-floppy --fs-uuid --set=root 66DD-8703
linux /boot/syslinux/vmlinuz changes=UUID:c012e6fd-3881-4876-bef8-12685e4b1b75/changes12
initrd /boot/syslinux/initrd.xz
}
Different drive
#GPT Tested also works
menuentry "Porteus Nemesis"{
set root='(hd0,1)'
search --no-floppy --fs-uuid --set=root putuuid here
chainloader /EFI/boot/bootx64.efi
#chainloader (${root})/EFI/boot/bootx64.efi #Use this if above doesntwork
}