Hopefully my last thread about V&V as I found the B.Boehm is text which I just do not understand well (likely my technical English is not that good).

http://csse.usc.edu/csse/TECHRPTS/1979/usccse79-501/usccse79-501.pdf

Basically he says that verification is about checking that products derived from requirements baseline must correspond to it and that deviation leads only to changes in these derived products (design, code). But he says it begins with design and ends with acceptance tests (you can check the V model inside).

The thing is, I have accepted ISO12207 in terms of all testing is validation, yet it does not make any sense here. In order to be sure the product complies with requirements (acceptance test) I need to test it. Also it says that validation problems means that requirements are bad and needs to be changed - which does not happen with testing that testers do, who just checks correspondence with requirements.