I can't explain how it happened Martin. I can not comment on the blue box, they won't let me...
Joking aside, I don't know how it happened. Prior to yesterday, with GRC open, when I went to help->about it told me I was using 3.7.8. I've had access to things like the new correlation estimator block and modulate vector block, which I understand are 3.7.8 toys from previous mailing list conversations I've had. Correct me if I'm wrong. Now help->about shows 3.7.7.1.
Pybombs handles the typical problems the link you posted addresses, like compile order and re-compiling in general. It uninstalled both uhd and gnuradio and then re-installed them both. Older flowgraphs work, but the ones using modulate vector and correlation estimator don't. I do have some custom blocks in those flowgraphs, would I need to re-build all custom blocks after an update?
Is it possible pybombs pointed to 3.7.8 by mistake for a day or two at some point, which happened to be when I last updated? How would I tell pybombs to install master HEAD, or are you recommending a git pull on gnuradio directly?