Thanks to the work of @robimarko and other contributors, DSA is getting close to the main tree for IPQ40xx devices.
Thanks to those that ported to the Linksys MR8300, I think my patches for the EA8300 should also work there.
If you've got access to an MR8300 and can test this new switch implementation, I'd greatly appreciate it. The source is at https://github.com/jeffsf/openwrt-ea8300 if you are able to build it yourself. If not, please PM me and I'll see what we can work out.
If you can't afford the downtime, or just don't want to, seeing the output of fw_printenv ethaddr would be helpful, along with the output of ip link. If the U-Boot environment returns
root@OpenWrt:~# fw_printenv ethaddr
ethaddr=00:03:7f:ba:db:ad
that's consistent with the EA8300 (and not "sensitive", as the "real" MAC address is stored elsewhere). If you want to send me the information over PM, that's OK.