I don't know if this is relevant, but just saw this web page related to Intel Graphics
There is a reference in the Configuration section that indicates that vga= should NOT be implemented. I see it is implemented in gtk.cfg. Perhaps this is irrelevant given the error failed to add i915 component master, but thought I would pass it along. Of course I am relatively ignorant regarding the whole install process but trying to provide whatever info I can in hopes that it might be useful.
Regards,
John Hart
I'm not irrational, I'm just quantum probabilistic.