The aim of this presentation is to demonstrate a scalable, modular, refinable methodology to design, assess and improve the trustability of an existing (20 years old), large (500k lines of C), open source (Eclipse/Polarsys IWG project POP) code generation suite using off-the-shelf, open-source, SAT/SMT verification tools (Yices), by adapting and optimizing the translation validation principle introduced by Pnueli et al. in 1998. This methodology results from the ANR project VERISYNC, in which we aimed at revisiting Pnueli's seminal work on translation validation using off-the-shelf, up-to-date, verification technology. In face of the enormous task at hand, the verification of a compiler infrastructure comprising around 500 000 lines of C code, we devised to narrow down and isolate the problem to the very data-structures manipulated by the infrastructure at the successive steps of code generation, in order to both optimize the whole verification process and make the implementation of a working prototype at all doable. Our presentation outlines the successive steps of this endeavour, from clock synthesis, static scheduling to target code production.