Enter the default gateway IP address into the URL bar: 192.168.100.1 (or 192.168.1.1 , depending on carrier configurations).
A: In most cases, yes—by using the same TFTP or web method. However, downgrading may factory reset the device. Some ISP firmwares block downgrades to prevent security vulnerabilities. Hg8247w5 Firmware Update
To safely source the official, signed firmware file for your specific device: Enter the default gateway IP address into the URL bar: 192