Sick UBlox m8n after long storage

Had a Pixhawk copter flying well for 3 years with a m8n-0-01 gps. Took it apart and used electronics in new copter after a year on shelf. Took over an hour to find 5 sats in open area. Next time 20 mins and very poor position. Tried to flash it with 3.01 in u- center (was 2.01) but it fails flashing. Now can only ever see max 3 satellites. Think it’s almost dead unless someone has any ideas. Think it’s genuine with flash memory chip.