So I purchased an EAP223 V2.6 as it was fairly inexpensive. When it arrived I noticed the FCC ID was 2AXJ4EAP225V4. Basically this device is Identical the to EAP225V4. I followed the instructions from the openwrt page to disable signing but when I tried to flash firmware in the stock UI it said device not supported and would not flash. To correct this I loaded the stock firmware in an hex editor and noticed this when I searched for an Ascii string
SupportList:
EAP225-Outdoor(TP-Link|UN|AC1200-D):1.0
*3.0 CA,JP,RU
EAP225(TP-Link|UN|AC1350-D):3.0
EAP225(TP-Link|UN|AC1350-D):3.20
*4.0 CA,EG,RU
EAP223(TP-Link|UN|AC1350-D):2.0 CA
Searching for this in the openwrt image I found
SupportList:
EAP225(TP-Link|UN|AC1350-D):3.0
EAP225(TP-Link|UN|AC1350-D):3.20
EAP225(TP-Link|UN|AC1350-D):4.0 CA
EAP225-Outdoor(TP-Link|UN|AC1200-D):1.0
EAP225-Outdoor(TP-Link|UN|AC1200-D):3.0 CA,JP
So I modified the openwrt image in the hex editor to read this.
SupportList:
EAP225(TP-Link|UN|AC1350-D):3.0
EAP225(TP-Link|UN|AC1350-D):3.20
EAP223(TP-Link|UN|AC1350-D):2.0 CA
EAP225-Outdoor(TP-Link|UN|AC1200-D):1.0
EAP225-Outdoor(TP-Link|UN|AC1200-D):3.0 CA,JP
After that I was able to flash and confirmed the device is working correctly. I am not a programmer so I would have no idea how to "add" this fix to the code if anyone wanted to. Either way I think it would help anyone who bought one of these devices and wanted to get it working on openwrt.