You changed config in firmware ( mod firmware ) ? You can use usb boot-up to recovery fw . Fimrware you find xiongmaitech website. ( auconfig.txt and update.img) Or you can recovery by UART port !
On XM board have 2 ic rom (24c08 and 25FL128). 24c08 with serial id + mac address, 25FL128 is OS. If board have 2 rom you can flash uboot ( flash tool xeltek ) and then flash all by TFTP. Your NVR is recovery (not lost ID + chanel number). If board only 1 rom 25FL128 you find and backup address...
i have a nvr board use Hi3536D chip all schematic same NBD8008 xiongmai hardware. I try flash uboot and then flash fw via UART, nvr boot up and run but only 1 frame and serial and mac is default. Maybe i lost rom chip 24c08 ( mac + serial ) or it include master rom ( address 3FC00 to 40000) can...