Nice, thanks for the reply; this is surprisingly undocumented online. Presumably if they got cornered and the module under repair was updatable via this mechanism they'd have some ability to use that system, then. I wonder how charitable they will be about using it for non-recall updates for customers who have solely chosen to opt out.

Rivian are probably the only major manufacturer I've never had a chance to look at in any RE capacity and I'm getting more curious by the second. The reaction their vehicles had to the infamous bricked-infotainment update actually represented a pretty good adherence to safety guidelines (the drivetrain as well as the speedometer and warning lights on the cluster still worked in a degraded format even when the infotainment was bricked) IMO, so they do seem to apply a reasonable degree of care.