So I got a N950 from Nokia, flashed it to beta2, but I cannot enable developer mode.
Every time I try, and confirm with OK, then accept the dependency notice, it then immediately says
Download failed
Can't complete the download.
Connection do the application provider was lost. Try again later.

And Try Again does the same.
I have tried many times, as well as rebooting, enabing installing apps from non-store locations, updating the applications (apt-get update I guess) and trying again on a different day and time...

Without more information in the error message, and without a terminal (catch 22...), I can't find out what it's trying to download exactly, to see if it actually exists..