The immutable ROM that finds firmware and jumps to it is indeed usually proprietary, but since it's tiny and immutable, it's considered "part of hardware" and is okay even for the FSF "Respects your Freedom" certification.
The one mutable/loadable blob the i.MX8 requires is firmware for the DDR4 PHY (not training code you run on the CPU, but something that runs on the PHY apparently??) and they're using an embedded tiny cortex-M4 core to just load it: https://puri.sm/posts/librem5-solving-the-first-fsf-ryf-hurd...
(IMO, that's a silly requirement from the FSF, I think keeping the main CPU free of blobs that it doesn't run i.e. blobs for other things does not have any meaningful benefits)
> (IMO, that's a silly requirement from the FSF, I think keeping the main CPU free of blobs that it doesn't run i.e. blobs for other things does not have any meaningful benefits)
Depends on how privileged the peripheral or subsystem is. And what data it is trusted with.
If it can't harm the main CPU and is properly confined then it's fine in my book.
The one mutable/loadable blob the i.MX8 requires is firmware for the DDR4 PHY (not training code you run on the CPU, but something that runs on the PHY apparently??) and they're using an embedded tiny cortex-M4 core to just load it: https://puri.sm/posts/librem5-solving-the-first-fsf-ryf-hurd...
(IMO, that's a silly requirement from the FSF, I think keeping the main CPU free of blobs that it doesn't run i.e. blobs for other things does not have any meaningful benefits)