The ISP may have phased out support for your specific hardware revision, or the newer firmware is for a different regional variant. Do not force an update.
To avoid "bricking" your device, follow these verified steps for FiberHome routers : HG6245D Firmware - vsociety - Vicarius hg6245d firmware download verified
To ensure network security and device stability, use only officially recognized channels to source your files. 1. Contact Your Internet Service Provider (ISP) The ISP may have phased out support for