Glo How do I upgrade Firmaware of a GLO?

Hi folks, I own a german GLO. I would like to test / install a new firmware as posted as zip file in the threads above. I unzipped the file and copied once the whole folder and in a second try only the contents of the firmware zip folder to the root directory of the glo. Then did a hadrware reset (with the small hole / button). But nothing happens.
Do I miss something? How can I tell the GLO. Hey you have got a new firmware on your SD - please install it.

Can someone be so kind and gice me a hint....
Thank you very much! :thumbsup: