Archive named for the P-660RU-T1v3s device, a duplicate marked (1), but its size is only 280 bytes, far too small to hold any firmware image. It is most likely empty, broken or a failed upload and should not be relied on. Technicians looking for this modem firmware should use one of the larger copies instead. Whatever image you finally choose, verify the hardware revision, back up the existing flash first, and check the file length matches the chip capacity.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @afsbiosfree. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.
Back up your own chip before writing any dump, and match the full board number and revision. Flashing guide →