[U-Boot] ARM64: armada3720: strange u-boot freeze (how to debug?)

[Marek Behún]

Hello,
during my development for U-Boot on Turris Mox I keep encountering
this strange bug when sometimes U-Boot gets compiled in such a way that
it freezes after printing the first line:

  U-Boot 2018.11-rc3-00065-gfc69da4cb1-dirty (Nov 08 2018 - 15:51:52
  +0100)

This bug disappears if I change something, for example a add a
puts("lol\n"); somewhere, or change the version of the compiler.

It seems like some unaligned access, or maybe the compiler sometimes
generates wrong instruction (but all gcc versions from 6 to 8 do this
sometimes).

How should I find out what the issue is?

Thank you.

Marek Behun