I've an old GPON ONT Router from Huawei, the HG850. It was provided by an ISP that no longer exists, and I would like to use it in another ISP (because it provides more ethernet ports and voip). I'm aware the process can be hard, however I've a friend on the other ISP that can me help me with the configuration down the line.
Here is the problem: none of us is able to use the telnet login of the HG850 to reconfigure it. We believe the old ISP changed the default login data:
(The preset user name of the terminal is root and the password is admin.)
Here is a link to the manual: https://cdn.iklive.eu/tcb13/2018/378621157-31401177-EchoLife-HG850-GPON-Terminal-Service-Manual-V100R001-02.pdf
Since there are a lot of hardware experts in this forum I would be really grateful if someone can provide us with a way to reset the device to default settings or hack the login somehow. My first thought was to check for a reset button or a JTAG / serial interface, however there isn't anything visible / properly marked on the device. Here are some pictures of the board (can take more):
On the last picture J2 looks like part of a JTAG / UART port. Does someone have some knowledge about this ONT? Is there a way I can reset it to default settings?
Many thanks in advance!