The flash chip may be physically damaged, or you flashed a build meant for a different hardware revision. To help you get your router configured correctly, tell me:

Some users have reported that their specific HG532e model or ISP-customized version does not have a "Firmware Upgrade" option in the user interface. In this case, your only options are to seek out custom, unofficial firmware or use hardware flashing methods, which are only recommended for advanced users.

You need the original firmware for three main reasons: