Hey @hansamann Yep, many people have registered their LoPys as gateways on TTN. Usually if it doesn't show up as connected its either a gateway ID mismatch (make sure it's the same in TTN and your configuration) or sometimes TTN has problems showing the connected status, try to use some nodes and see if they appear under traffic. If you can post your gateway ID I can also check on the master list at http://noc.thethingsnetwork.org:8085/api/v2/gateways (btw are you hansamann on Twitter? If so we met at MakerFaire UK a few years back, I was helping out Andreas Kopp. Cool to see you here)

Correction to my previous comment, the default Marvin code contains the send_LoRa_Command("mac set adr on"); command. So indeed it switches on ADR on purpose and not by default.