When a method has a parameter of type []byte, the underlying NeoVM type could be a ByteString or a Buffer at runtime. With the type of a parameter declared as []byte, that parameter can be passed to methods that require a Buffer on the NeoVM. If the passed parameter is of type ByteString the execution will fail at runtime.

Suggestion:

Add a compiler configuration that would prepend a type check on the NeoVM and convert the argument to a buffer if necessary. E.g., prepending something like the following before any LDARG opcode with an index to a parameter of the Java type []byte:

DUP
ISTYPE 30 (type buffer)
JMPIF 3 (jump over the convert opcode)
CONVERT 30