You could simply repack the savegame into an .LSV instead of running the game, saving, reextracting, editing meta.lsx and repacking the LSV.
Also, D:OS 2 also hashes/verifies meta.lsf, so the savegame corruption warning would still trigger after manually editing the Sanity flag.
weird... repacking the save never fixed the error message for me. but if that works for others great! makes the process even easier.
about the corruption warning still showing after editing the sanity flag: i don't have D:OS 2 yet and i have no idea, this was only meant for D:OS1EE.