>I don't think this has changed at all since.

There is common knowledge to suggest that it is not the case (or maybe is no longer the case):

>Mainstream smartphones do not provide DMA access from the baseband to the application processor's memory... Yes, getting baseband access then lets you monitor regular voice and SMS comms. But no, it does not instantly compromise the AP so using the Signal app would still be secure. https://news.ycombinator.com/item?id=10906488

>Apple mitigates baseband processor vulnerabilities by putting it behind what's essentially an IOMMU. https://news.ycombinator.com/item?id=29440154

>This is false FUD that keeps being repeated. It's not true. No iPhone ever has had a baseband with DMA access to my knowledge, and modern Qualcomm devices have advanced IOMMU systems to firewall away the baseband from the rest of system memory. I'm sure some phones somewhere existed where the baseband was privileged, but it's not the norm. https://news.ycombinator.com/item?id=30393283

>Connecting a cellular radio via USB provides far less isolation than the approach of a tiny kernel driver connected to an IOMMU isolated cellular radio on mainstream devices. USB has immense complexity and attack surface, especially with a standard Linux kernel configuration. Forensic data extraction companies mostly haven't bothered using attack vectors other than USB due to it being such a weak point. Many of the things people claim about cellular radios in mainstream smartphones are largely not true and they're missing that other radios are implemented in a very comparable way. https://news.ycombinator.com/item?id=46841004