If your Base station VMB3000 won't update firmware. call support on the phone!
I've had trouble with my VMB3000 base station not updating its firmware for weeks (firmware on the base station: 184.108.40.206_2798). I finally decided to call support on the phone after countless attempts at the standard update procedure, several power-cycle attempts, and even a "hard reset" and removing/adding the base station every time. None of it helped.
The phone call went through a speed test of my internet connection, followed by another "hard reset" and attempting to add the base station back with the Arlo app on Android. When the app produced the message that the firmware could not be updated, the support agent authorized a replacement unit to be sent out.
If you're in the same boat, the support call avenue seems to be your best way to get this problem resolved.