Vu+ Duo no longer flashes using usb ports?

Hi there.
I have a VU+ Duo. Had it for 6 months now. It has stopped flashing using the usb ports.
I have flashed the receiver over the internet while I had OPEN ATV image installed. But i have flashed the receiver with a VTI image that I like.
But not the up to date image. And so I do not have the software installed to upgrade.
Is there a file that I can add to my receiver that will allow me to download and install any one of the images that can be used on this receiver.
Please note that I will have to use the receiver and a hard dive to download and install future images. As when trying to flash by usb. The receiver will not flash but will just boots into the system that I have installed.
Also when I did flash a new image of the OPEN ATV. A message came up saying "2 eraseblocks corrupt". Is this why I can no longer flash with usb.
I have read several times that this is nothing new. Maybe have to return the receiver.
Thank you.
Stuart.

I will try another usb stick when my neighbour returns home. But I think that it is a problem with the flash memory blocks?
Thank you for taking the time to reply to my post.

Problem solved with a different usb stick.
Thanks all.