Unable to downgrade firmware

Hi all,

We had a Wyse Terminal from our Supplier which was DOA, They advised to go to Dell directly for warranty replacement. We did and a brand new Wyse 5070 was sent out. We've come to set this up but the firmware is too high version for what we use.

I spoke to Dell support and downloaded the V8.6_710 PCoIP Merlin OS and built a USB to downgrade it.

I followed a guide I found on the Dell site https://www.dell.com/support/kbdoc/en-uk/000126362/how-to-use-the-dell-wyse-usb-imaging-tool-to-update-firmware to build the usb as I was having issues at first. The guide says o use the xml file that's in the folder. I've built the usb and tried to image the machine. It starts fine but whene it gets to the "Operating systems (In Progress) screen, it will get to 100% and sit there. It's been left overnight but next day it's still on that screen.

Have I build the USB correctly or am I being impatient?

Thanks.