I was able to update Annke FCD800 I91EV to HikVision firmware directly from WebUI upgrade option.
Model used
DS-2CD1T83G2P-LIUF/S(L)(RB)
https://www.hikvision.com/en/products/IP-Products/Network-Cameras/value-series/ds-2cd1t83g2p-liuf-s-l--rb-/
Direct upgrade in WEBUI
Firmware_V5.8.11_251029...