NFLOG on Merlin?

[infinality]

I'm trying to do packet logging, and I've successfully done so on Centos/Fedora with NFLOG by adding a line like this to iptables:

-A LOG_DROP -j NFLOG --nflog-group 40

On Centos, I can run this command and get a list of interfaces that includes nflog:
$ tcpdump -D
1.nflog (Linux netfilter log (NFLOG) interface)
2.nfqueue (Linux netfilter queue (NFQUEUE) interface)
3.ens192
4.any (Pseudo-device that captures on all interfaces)
5.lo [Loopback]

On Merlin (latest version), I get this however:

# tcpdump -D
1.eth0 [Up, Running]
2.br0 [Up, Running]
3.eth1 [Up, Running]
4.vlan1 [Up, Running]
5.eth2 [Up, Running]
6.tun21 [Up, Running]
7.lo [Up, Running, Loopback]
8.any (Pseudo-device that captures on all interfaces) [Up, Running]
9.dpsta [none]
10.ifb0 [none]
11.ifb1 [none]
12.vlan2 [none]

There is no nflog interface listed. I have the relevant entware packages installed (libnfnetlink, etc.), and I can see nf_log modules are loaded:

# cat /proc/net/netfilter/nf_log
0 NONE (nfnetlink_log)
1 NONE (nfnetlink_log)
2 ipt_LOG (nfnetlink_log,ipt_LOG)
3 NONE (nfnetlink_log)
4 NONE (nfnetlink_log)
5 NONE (nfnetlink_log)
6 NONE (nfnetlink_log)
7 NONE (nfnetlink_log)
8 NONE (nfnetlink_log)
9 NONE (nfnetlink_log)
10 ip6t_LOG (nfnetlink_log,ip6t_LOG)
11 NONE (nfnetlink_log)
12 NONE (nfnetlink_log)

What am I missing? I searched the forum and google but was unable to find anything specifically related to Merlin and NFLOG.