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iptables conntrack issues am335x Starter Kit SDK 6

I have an am335x Starter Kit with version 6 of the SDK pre-built image. I have also tried this with SDK 7, but I am using SDK 6 since it seems to be the latest image with wifi support.

I am trying to setup a stateful firewall using the following iptables commands:

iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -N TCP
iptables -N UDP
iptables -A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -i eth0 -j ACCEPT
iptables -A INPUT -i wlan0 -j ACCEPT
iptables -A INPUT -m conntrack --ctstate INVALID -j DROP
iptables -A INPUT -p icmp --icmp-type 8 -m conntrack --ctstate NEW -j ACCEPT
iptables -A INPUT -p udp -m conntrack --ctstate NEW -j UDP
iptables -A INPUT -p tcp --syn -m conntrack --ctstate NEW -j TCP
iptables -A INPUT -p udp -j REJECT --reject-with icmp-port-unreachable
iptables -A INPUT -p tcp -j REJECT --reject-with tcp-rst
iptables -A INPUT -j REJECT --reject-with icmp-proto-unreachable

iptables -A TCP -p tcp --dport 22 -j ACCEPT

On any of the commands involving '-m conntrack', it fails with:

iptables: No chain/target/match by that name.

'modprobe nf_conntrack' did not help.

I tried purposefully misspelling parts of the command like ESTABLISHED and ACCEPT, and they result in a different error (couldn't load target). It seems to indicate the error is complaining about the '-A INPUT' portion of the command, yet it works perfectly fine with other commands.

Any help is much appreciated.