File Format?

Hello I’m new to the comodo forums. But anyway here we go. I recently tried to put comodo rescue disk on my usb just in case anything happans. 8). Well i just want to know why it has to be FAT filesystem? I have a exfat 64 gb PNY and i do not want to reformat it to fat because of the 4 gb file transfer limit. Also another question will there ever be support for exfat?
Thats all thanks for your time!