I did not care about any DRM stuff.
But I found it being a real lockin procedure since it was impossible to unlock the bootloader unless I
* actually started the phone (not only vol-up start),
* set up the android,
* enabled developer mode by clicking 7-8 times on the build item in the about/system in settings section, and
* then checked the then appeared "allow bootloader unlock" as the last step.

Not sure if it will help you or fit your situation, but to me this was a completely wasteful step of an hour or so. They claim it is for protecting active installations that you cannot allow direct flash of phones in use, but it was no active installation (and never used before) since I had to actually set it up and avoid installing and configuring phone-home features etc ... I only wanted to unlock and flash.
The good part of it was that it took two minutes flat to flash the image until booting SailfishOS after the bootloader unlock (which took only a fraction of a second).

Cheers,