Thanks for quick reply,
I'm on the latest firmware already and I have tried using the PDP value.
It's set to IPv4/IPv6 and if I chose IPv6 it get stuck on state disconnected.
I got a Huawei mobile router (Huawei b535) from my ISP and now when hooking up to that router again to test I seem to get an IPv6-address, but trying ipv6-test.com doesn't yield me any public ip. And further googling showed me that the address I got from the router was a ULA-address (Unique Local Address) fc00::/7
I'll contact my ISP and see what can be changed as I'm able to get an IPv6-address on my phone that has the same ISP.
Thanks for your help and I'll get back if I have further questions.