WinXP cannot be installed under UEFI but it can be started if you have previously installed it in legacy mode or has be deployed using sysprep.Can it have any necessary changes to the installer so that installation under EFI / UEFI is possible not only from CD/DVD, but also from USB? If it is possible, then please upload that installer iso (at least the XP SP2 x64) at your earliest (after doing all necessary changes, if any).