Firmware XDJ-XZ update freezes at 33%

I'm trying to update to 1.24 Main, ERP/SUB, JOG-L and Jog -R are working fine.
But 'Mixer' is stuck at 33%.
How can I solve this?
I got the XDJ XZ last Saturday and 2 days later it doesn't work at all!
I have found 3 other people online with the exact same problem.
All at exactly 33% so this can't be a coincidence.

And yes; I have already used several correctly formatted USB sticks.