ZoneRunner and custom root hints

Hi,

I am fighting with customizing root hints used by ZoneRunner (on VE 13.0.0HF2), I did everything according to this article Configuring a root.hint zone for use with the BIG-IP DNS system but I failed.

If I paste content of the file get from link in article root hints then

dig . NS @

is working.

If I modify IP in any entry in db.external.named.root. (doing stop start for named and zrd after mod)

like changing

.                        3600000      NS    A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET.      3600000      A     198.41.0.4
A.ROOT-SERVERS.NET.      3600000      AAAA  2001:503:ba3e::2:30

to

.                        3600000      NS    A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET.      3600000      A     198.41.0.5
A.ROOT-SERVERS.NET.      3600000      AAAA  2001:503:ba3e::2:30

I am getting exactly same response to my query - no change in IP for A.ROOT-SERVERS.NET

If I delete all entries and leave something like that:

.                        3600000      NS    mydns.test.com.
mydns.test.com.      3600000      A     192.168.1.254
;A.ROOT-SERVERS.NET.      3600000      AAAA  2001:503:ba3e::2:30

then response to the same query is server failure

What I am doing wrong then, or maybe it's a bug?

My goal is to send all queries from LDNS to my DNS server that then should be responsible to provide answer to A query.

In situation like described BIG-IP is handling recursion, sending requests to all NS in a chain (starting from root) - not what I need.

Piotr