From TFA: https://puri.sm/posts/librem5-solving-the-first-fsf-ryf-hurd...
> The RYF has a “secondary processor” exclusion that can be granted on a case by case basis. We will leverage this exclusion to load and train the DDR PHY on the i.MX 8. We will use a secondary processor to keep binary blobs out of u-boot and the kernel.
That's simply not true. Users can upgrade those firmwares if they want (and absolutely no weird tricks like disassembling or soldering are necessary for that). PureOS doesn't distribute any non-free updates, but if you want, you absolutely can reflash these blobs.