Ultraloq Smart Locks don't support the master key function.
If you want to rekey the cylinder or duplicate your keys for the U-Bolt series, please submit a ticket then share this FAQ Description of the Ultraloq U-Bolt Series Cylinder Lock with the locksmith.
> Can I use my existing deadbolt cylinder with my existing keys? The lease does not allow us to change keys.
No. We don't recommend using a third-party cylinder.