Dropbear fails to work with -Ofast optimization

If I set CONFIG_TARGET_OPTIMIZATION to -Ofast in kernel .config instead of -Os dropbear hangs upon connect.
Is there any way to set package specitic optimizations?

As a workaround I remove the package from my system and install dropbear package from the offical repro instead.

That's all you need, don't bother with the rest (it's not worth it).

Thanks, much appricated!