@Photob
Hi, there is no method to restore the unit to factory firmware. Where are you located in?
In my opinion, if you don't meet any further issues with the EAP, no worry about it too much. The only thing you need to pay attention to is your local wireless regulations.
As far as I know, the difference between the CA firmware and the US firmware is the wireless channels that the AP can work at. In Canada, according to its wireless regulations, only 5G Band 4 is allowed for an outdoor wireless device. But people in the USA can use both 5G Band 1 and Band 4. If you upgrade your EAP outdoor to CA firmware, then it will only support 5G Band 4, the DFS channel.
Cheers.