Oh, so you did LUKS over LVM then. I did the opposite.
I doubt mine is really safer (preventing access to the LVM partitions in the
first place); plus yours allows stretching partitions over several physical
disks. My LVM is set in stone instead, so to speak (But I don't need the
feature on that machine).
Unfortunately, I tried removing the USB stick several times without success,
even changing the installation path to /dev/sdb didn't work either. I think I
even tried /dev/mapper/herd-of-cats_main.
Also there's no CD drive on that machine. Why would a CD be different btw?
Because it's not seen as /dev/sdX maybe?