Uniquely Identifying USB filesystem possible?

[Harry Hirte]

Hello,

I am trying to read data from a USB-Stick when booting from grubx64.efi
This basically only works if I specify the device as (hd0).
I am looking for a possibility to uniquely identify the USB-stick.
I build my grubx64.efi using 

grub-mkimage ... -c <file> -o ... luks2 part_gpt cryptodisk ... search_fs_uuid 
usb

with the contents of <file>:

insmod usb
insmod search_fs_uuid
set crypto_uuid=abb...-x-x-x 
search.fs_uuid 24cc...-x-x-x  keyfile
cryptomount -k ($keyfile)0+ -O xxx -S yyy -u $crypto_uuid
set root=lvm/vg0-root
set prefix=(lvm/vg0-boot)/grub
insmod normal
normal

the USB-stick is configured as luks-device with the UUID 24cc...
As mentioned, this does not work - even using cryptomount with this UUID fails.
Is there any other way to get a uniqe identification for a filesystem on a 
USB-stick?

Thanks + kind regards