KXTVA-50 keeps restarting itself.
While I try to do a factory reset I only get 3 blinks only while alarm light is on and one run blink and it reboots.
Please help if any one had this issue

Check that all the switches on the unit are off.
it sounds like it is not starting, the older units had hard drives and this would be a sign of a failed drive.

it could be a failed flash drive. but have seen a switch 4 on cause this as well

You are right it looks like flash drive fails
Changing switch position to 0 or 1 doesn't bring any changes it keep restarting
Is there any option ?

I had one that was doing that and it was really odd it turned out to be something happening with the switch it was plugged into. Removed the Ethernet cable and it stopped rebooting.

No Ethernet port only USB

It's DEAD.