We can produce our own LiveUSB manually. The following are the steps that based on Arch Linux distro.

1. Build a kernel that supports AUFS, SquashFS, and optionally vfat support. So that we can mount these filesystems. In Arch Linux, we can build linux-pf for these supports. This package can be found from AUR.

2.  Then we can generate the initramfs. In Arch Linux, we can use mkinitcpio to create an initramfs image. For instance,