Multiple USB Blasters on the same PC

Thank you stonie and nvs.

All is well with my RevA blaster, but have ordered another which no doubt will be RevB.

I had no idea the blaster used the same chip as my application, and even less that mprog would re-program something it was not plugged into.

While the solution is to unplug the blaster while setting up my board, it does raise a question as to why the blaster, as a commercial product, is not protected from over-writing. Maybe it's not possible. I will investigate this on my board as I don't want it to be exposed in this way on the final product.