Version 3.92 allocates new nvmem location to support long passwords (32 characters) and SNMP community string (64 characters). In Version 3.92, on first reboot after migration from previous version, the new password and community string areas are installed and old settings (if any) are copied to new location. Version 3.92 is case-sensitive and stores passwords and SNMP community strings as they are entered on the CLI. In previous versions the case-sensitivity was not preserved and passwords and community strings were converted internally - passwords were stored in all uppercase and community strings in all lowercase. The parser allowed the user to type in any case as long as the letters matched.
When the user upgrades to Version 3.92, the mixed case passwords and SNMP community strings from previous versions are stored as lower case characters. After the upgrade, the user should verify the password and community string and set them as desired.
Recovering Passwords from Console Ports in Firmware click this link.
http://www.cisco.com/en/US/docs/cable/rfswitch/ubr3x10/configuration/guide/rfswcf36.html#wp967107