EnGenius EWS550AP

I have a senao WAP7301AG which is the sample model of the EnGenius EWS550AP It came with OpenWRT installed. Im trying to update it to a newer OpenWRT firmware but I am stuck in where to start. I have 50 of these devices that I was going to deploy.

root@OpenWrt:~# cat /etc/openwrt_release
DISTRIB_ID="OpenWrt"
DISTRIB_RELEASE="Bleeding Edge"
DISTRIB_REVISION="r43761"
DISTRIB_CODENAME="barrier_breaker"
DISTRIB_TARGET="ipq806x/generic"
DISTRIB_DESCRIPTION="OpenWrt Barrier Breaker r43761"
DISTRIB_TAINTS="no-all busybox override"

none of them is supported, but the ipq806x is a common arch here, making it supportable.

Okay, where would I start to building the firmware? I'm new to OpenWrt.