The tar ball contains a lot of stuff. More than just some binary blobs. If you look at it, it also contains config files, data files, libs (.so). All also “protected” with funny headers “Qualcomm Technologies Proprietary and Confidential.” The “real” proprietary firmware (.fw,.bin,.b*) mostly ends up in “product/FP2/system/etc/firmware”.
I don’t see a problem with the last part (/etc/firmware), but I’m not so sure about the rest. I think the images would have to be opened and “repacked” on the users machine to add the libs again I think. And even linking the code … I’m not so sure about that, but I would like to see an official answer on this. I guess it’s a no, but a automatic build service could still be provided by FP if they find the manpower.
Or to put it very simple:
a) Build working code without "bin blobs"
b) Build working code with “bin blobs”
Make a diff/compare checksums. Check if you can make “a” match “b” just by copying files from the “bin blob” tarball into the images.