Upgrade options for Engenius ECB350A

I have an Engenius ECB350 running as AP-only for a number of years- It generally runs fine.

The ECB350 appears to use an older custom OpenWRT firmware (KAMIKAZE (bleeding edge, r20146), possibly 8.09). The vendor UI is pretty restrictive and clunky, several features don't work properly, and the opkg config points to a 404 url (http://downloads.openwrt.org/snapshots/trunk/senao/packages), so there's no easy way to upgrade existing packages or install new ones.

I'd like to see if I can upgrade the AP firmware to a more recent version of OpenWRT. Engenius EoLed this device some time ago and the most recent Engenius firmware available for it is still very old.

The OpenWRT firmware selector has a minimal kernel image available for the ECB350v1 (https://openwrt.org/toh/hwdata/engenius/engenius_ecb350_v1), however I believe my device is actually an ECB350A (https://fccid.io/A8J-ECB350A), which may have a different CPU and chipset than the ECB350. My device appears to have a AR9344 CPU and AR9340 chipset (compared to AR7242 CPU/AR9283 chipset listed on the ECB350v1 ToH page).

Is there a viable upgrade path for this device to a recent version of OpenWRT? If not, how easy/hard would it be to create one?

Thanks!

It looks like there is no support for the ECB350A, and likely never will be.

For the ECB350v1 the last sysupgrade image was 21.02.7.
Now it fell out of support completely:
https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=60061b5c26b65004377a886f917bcd3005e97dad

For new devices it's usually this guides:
https://openwrt.org/docs/guide-developer/adding_new_device
https://openwrt.org/docs/guide-developer/add.new.device

But for this limited hardware it's just not worth the effort.
It's much easier to get another, well supported, device with better specs.