I have seen a few people talk about their experience with this issue and I wanted to share how we fixed one instance of it:

The symptom is that the program will just hang completely on bootup. There's no defmt output logs, no errors printed, just nothing seems to happen. 

The cause was found to be a large static linked in a different memory section that we were trying to initialize. Since it wasn't a const init, the value was getting allocated on the init functions stack and causes an overflow. flip-link doesn't catch this sort of overflow, so it must be reaching some hard fault handler and not flushing the defmt log buffer, hence no logs.

The solution was to make that large object use a const init, the problem goes away. As far I know, there is no way to initialize a static variable that is larger than your stack if the init is not const. I tried to use `static_cell::StaticCell::init_with` which claims to do just that, but I still saw the issue.