[ianlevesque]

Secure boot doesn’t fix the first one because a buffer overflow exploit won’t get verified and prevented by the boot signature verification. As with all DRM schemes it mostly only hurts your legitimate customers.

The second is uninteresting because often they can just get your exact product off the same assembly line after hours.

I’ve heard of a third, which is a concern that having the option to load unapproved software somehow compromises the security of everyone else. I don’t buy it.

[fragmede]

Even if you don't agree with it, the two lissues for the third point are that an RCE lets an attacker irreversibly modify the firmware remotely, or that the user will intentionally install an older unsupported version that contains an RCE. Vendor controlled firmware also has this issue, but that's the "compromises the security of everyone" with #3 because the attacker can now use the device as a VPN or as part of a DDOS botnet.