hi everyone.

Could someone please help me where i can get old firmware versions for gpsmap 557xs.
I am stuck on version 6.4 and it will not update.
something weird happening with device as after a factory reset when i make any changes and reboot device, it has forgotten all the changes.
I delete all the waypoints and after re-boot they are all back...
I want to try downgrade to older versions and try upgrade from there.
Could you point me to older version and maybe even version 6.50?
Thanks