Yeah, the radeon module in newer kernels falls over and dies when the
proprietary blobs are not present. The current options are to use an old
kernel, help Linux-libre gain blobless activation of that card (this is
already possible with evergreen radeon cards starting from kernel version
4.8) or replace the video card (with something not radeon.)
At a high level, the idea of enabling blobless activation involves making the
blob loading code a conditional (so that it doesn't fall over & die when it's
not present) and see if the card still works. If it does, it can be
incorporated into Linux-libre.
http://www.fsfla.org/pipermail/linux-libre/2016-May/003217.html
http://www.fsfla.org/pipermail/linux-libre/2016-July/003224.html
http://www.fsfla.org/pipermail/linux-libre/2016-August/003228.html
