Dell Wyse 5060 ThinOS upgrade from USB - boot problem

Dear Sirs,

i have a problem on a Wyse 5060 thin client.

The thin client originally was purchased with ThinOS (i can see this in the system configuration related to this service tag: SRV,SW,THINOS,V8.3.1,5060,ENG). As i purchased it used, the vendor deleted the OS from it before selling... maybe to clean up data (which is not an issue in a thin client anyway...) So i need to restore the ThinOS to use this device with a PCoIP Teradici workstation.

I downloaded the "ThinOS 8.6_013 English Merlin Image file for Dell Wyse 5060 thin clients with PCoIP" file from dell.com/support and i created a USB key using "Dell Wyse USB Imaging tool" downloaded from https://ftp.dell.com/wyse/USBFT/ - i used version 3.1.0

The thin client will not boot from USB. I tried to disable secure boot, to enable boot from USB and also the "Legacy/UEFI/Both" boot types in the BIOS.

Nothing... the system does not boot.

Can you help me please?

Thank You

Andrea Naggi