I am trying to do this too, I am using proxy, I have modified the default files in the 3 folders under C:\Program Files\Theopenem\tftpboot\proxy (bios, efi32, efi64) but the changes do make any difference, even if I try to rename a label. Then I seemed to remember I needed to regenerate boot files, and that made no difference other than resting the default files back to default setting of 50