After EWC fresh install v9.21 and upgrade to v 10.01.01.0129 ap 3801i not detecting.
AP 3801i used to be connected to dead/bricked controller. SSH'ed into AP and reset to factory.
AP getting IP from DHCP - SSH'ed onto AP and I can ping controller from AP.
Tried adding AP manually from controller by specifying AP serial followed by 0000 - AP added. I specified AP static address. AP did not come online even after reboot.
I searched and read various content on the KB and in gtac. no luck.