I wrote an .img file containing a custom debian distro to a usb stick via win32diskimager program. Unfortunately it doesn't boot on my older motherboard, returning: SYSLINUX: No DEFAULT or UI ...
I formatted my ~200GB HDD with RMPrepUSB to FAT32 and with syslinux bootloader. Used XBoot to "Create USB" with debian-6.0.6-amd64-netinst.iso inside. In linux.cfg it shows up as: ### MENU START ...