Unlocking windows 8.1 developer phone–nokia lumia 851 payas you go (tmobile)

it wasn’t easy.

But here is my GUESS at what must be true – on the basis of error prompts and what I fiddled to eventually make something work. I.e. register the phone for development.

1. obviously update to 8.1 OS, and use the 8.1 phone registration tool (not the 8.0 version).

2. Insert the SIM care (the right way!)

3. Let the phone use the sim card and telco circuit to set the time

4. ensure an internet connection exists ON THE PHONE (e.g. wifi).

There was also a REALLYT nasty gotcha – that you has to install a particular windows update file – since the SSL connection made to the developer registration site would not recognize intermediate certs (since AIA fields don’t ACTUALLY resolve to  Microsoft addresses, for auto-learning of intermediate cert).

(More NSA complicity…. in the sense for FORCING folks to use windows update for national infrastructure key management)


yes, I do have a paid up windows phone developer license (bound to a liveid); and yes the phone sort of ties into that liveid, too. Whether these facts are relevant…. for unlocking I don’t know.


About home_pw

Computer Programmer who often does network administration with focus on security servers. Sometimes plays at slot machine programming.
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