Hi there,
I know, It is seems to me it’s in between open and closed , LOL.
The signed Bootloader maybe is why it’s locked or something, I just don’t get the proprietary of it, Same with the "AT " command set, Although I did see an open source version of that at some point in the research. We really need a full OPEN source Dev platform, NONE of the current offerings are that, IMO sux and slows the development of the total TECH.
I hope for more GOOD stuff in this area. 
GL 
PJ 