you can't update 2 Devialets from the same SD Card. After the first amp has been updated it is deleting some files. If you use this card in the second amp it is updating fast but in fact it is not updating anything. YOu have to copy all files again to the sd card before you update the second amp. Maybe this was the problem ?
It will also take more than a minute on a 250 if it works.
It will also take more than a minute on a 250 if it works.