See the blog post, the GPLv2 goes further than what you suggest.

minhaz23 · 2024-10-19T06:02:43 1729317763

So if my Toyota head unit has FOSS they can provide that source code to me if I ask?

numpad0 · 2024-10-19T15:57:34 1729353454

  https://www.denso.com/global/en/opensource/ivi/toyota/

ChocolateGod · 2024-10-19T14:31:26 1729348286

For the parts covered under GPL, yes, which includes the kernel (if it uses Linux).

If they're covered under a more permissive license (e.g. Apache, MIT) you're out of luck as these don't require redistribution of derivative work source code, only attribution.