Officially from the horses mouth:
Hello Daniel,
The Zgemma is not an official product and not listed as one of our Linux tested receivers. Zgemma is a Chinese brand that is produced by many manufacturers in Shenzhen. These are not stable high end receivers and support is limited.*
All of the HMP-combo tuners have been vigorously tested it works for Vu+, Xtrend and GigaBlue brands.*
Please be reminded the HMP-Combo Tuners are genuine products.
How much did you pay for the Zgemma? Did you download the firmware directly from OpenATV? **
Kind regards,