There's an IOMMU:
> Is the baseband isolated? > Yes, the baseband is isolated on all of the officially supported devices. Memory access is partitioned by the IOMMU and limited to internal memory and memory shared by the driver implementations. [...]
https://grapheneos.org/faq#baseband-isolation
> GrapheneOS cannot really influence this, but hardened_malloc could conceivably help.
They can and do, see above. But I don't see how hardened_malloc is related to the baseband doing DMA.
To answer your question, I thought it might just be slightly harder to extract secrets or exploit a running process directly. Thats all I was saying.
I do this on iOS I’m sure it’s do-able on GrapheneOS and hopefully on Android too.
Essentially, 5G is sort of a lie. Phones spend a lot of time exchanging information via 4g/lte, and just like 2g/3g and 3g/4g, there are simply downgrades that can be performed in the field, without getting too far into the weeds.
5G matters not for this.