Hello

If you want to create Remastersys with EFI (and BIOS) version - read me

1) Download Debian EFI
http://cdimage.debian.org/cdimage/unofficial/efi-development/upload4/We must choose a version for our architecture - or download multiarch version
2) VirtualBox
Use VirtualBox with System -> Enable EFI, to use EFI
3) Install
Install Debian in the same configuration what you need, BUT in Partition - Set Manual, and create a partition like that
100MB - EFIBoot
1GB (or whatever) - Swap Area
x GB - /
4) (Recommended) Install X server with DE (not required, but recommended)
5) Install Remastersys
http://78.8.9.23/slawek/.sunrise/1remastersysDownload it and run as Root - You should have Remastersys for EFI version (little changes with normal) - This Remastersys use GRUB, XZ Compresion, doesn't have Remastersys-installer and maybe something else

6) (Recommended) Install Live-Installer (Mint Debian Installer)
http://78.8.9.23/slawek/.sunrise/1liveinstallerDownload it and Run as Root - It should give you a MDI compatibility with Remastersys (and EFI)
7) Build your LiveCD
remastersys backup
8) Create new Virtual Machine for test
It is probably all, if you have a question - use simple words :P
Fervi