I bought three Efento devices to test. Is there any one else who have tested that? The modem is ublox SARA-R410M.
Assuming their firmware isn’t doing something funky with the modem, our own Novas use the SARA-R410M so should be entirely compatible.
The hardware wasn’t the problem. It’s Hologram that not have NB-IOT coverage in Sweden. Works with Telia sims here.