Please help me.

After a firmware update for my router(to the v1.5), it seems that the WAN connection is unable to be established. The only thing it says (under the network tab) is that it is disconnected, and a constant yellow/orange light for the WAN LED.

I've asked my ISP if there's anything wrong on their side, and there's none. I've also asked if by chance my connection type was wrong (PPPoE, Dynamic IP, and checked the ID and password for good measure), which was also not the case.

The modem itself seems to be working fine, as I tried plugging it into an older original modem from the ISP which works.

Tried downgrading the firmware to the previous version but didn't work(perhaps a hard lock as I tried factory resetting it multiple times but it stayed at the v1.5).

Any help would be much appreciated.