home internet modem model kvd21

Basically I work nights, so the firmware update happens between 1am to 3am. My problem is the exact moment 1AM rolls around my internet is worthless. It is on ver. 16 the current is ver. 21. My modem will download the update to 100% but when it goes to install  the firmware it hangs at 0% for roughly 1 minute then reboots, never installing the firmware update. Then it just rinses and repeats for about 2 hours until yall try to stop updating it. This is every single night.