Try to reverse it (like sign[::-1] in Python).
Try to swap its halves (sign[len(sign)/2:] + sign[:len(sign)/2]).
Try to reverse its swapped halves too.
It is GOST: do you expect serialization unification?!
Try to reverse digest you are signing/verifying (like dgst[::-1] in Python).
It is GOST: do you expect serialization unification?!
No way! You still have not tried to reverse your binary private key, public key and swap its halves.
It is GOST: do you expect serialization unification?!