Smart lock upgrade from 1.3.9 - help needed

I got smart lock (2 pcs) as a gift 2 days ago with firmware 1.3.9. There’s new firmware available 1.10.3.
Tried to upgrade lock via iPhone (latest iOS) and Galaxy S20 (latest version Android), fails every time.
On iPhone upgrade fails at 97%, Android errors FF, 814. On Android phone Manage lock section is unavailable with error code FF. Bluetooth and bridge connection is active.
Locks were brand new, in sealed package.
Can somebody help? I might get an iPhone with older iOS version, maybe 12.4.5? Which one would be good for upgrade?

Try it with several Android phones. Also try to take out the batteries after an upload failed, because this will remove the old upload and force the app to start from 0% again.

It you still have problems, please contact our support via or for more detailed information.

This forum is focused on developer related issues.

Yeah sure, it’s developer forum.
Nuki support didn’t help. It’s bad that there’s no compatibility between old firmware and new ios. Also upgrade via multiple different android phones is not possible as manage lock section is unavailable with error FF.
I was forward looking but there r many problems…