VMG3312-T20A full factory firmware (with ROM-D)

Hello,

I am looking for a full factory firmware image (including ROM-D) for a Zyxel VMG3312-T20A.

My router seems to be ISP-customized. Even after a hardware reset, the admin password printed on the label does not work.
This strongly suggests that the device is using a custom ROM-D configuration from the ISP.

The firmware available on Zyxel support pages is only a very small upgrade file (~20 KB) and does not overwrite ROM-D, so it does not restore default credentials.

I have serial access to the bootloader (ZHAL) and I want to:

• flash a full factory image with ROM-D
• using TFTP from the bootloader interface

I am looking for any of the following:

• full factory firmware image for VMG3312-T20A
• ROM-D image
• full flash dump from a non-ISP / generic device
• recovery image that restores default admin login

If anyone has such an image or can share it (publicly or privately), I would be very grateful.

Thank you very much for any help!