Program Update

I've had a Devo 8S for about 3 years and have previously installed the relevant Deviation firmware. As I was still new to the Hobby I battled a bit with geting my head around the interface, so decided to revert back. The issue i have is that i can't get the TX to go into the "Program Update" mode. When i hold down the EXT button and power on i get USB Mode. Not sure what i'm doing wrong so any advice would be helpful.

A mistake I make all to often is holding the ENT button - which starts the USB interface - and not the the EXT button to go into update mode. Just to be sure, double check that.

Does the drive you've got show up as formatted? If not, then you may be starting with no buttons held, and it's going into USB mode because the drive isn't formatted. That could be a number of issues.