MySQL 4.1+ using old authentication

Consulta SQL:

SET old_passwords = 0;
UPDATE mysql.user SET Password = PASSWORD('testpass') WHERE User = 'testuser' limit 1;
SELECT LENGTH(Password) FROM mysql.user WHERE User = 'testuser';
FLUSH PRIVILEGES;

Modificar Archivo my.cnf
old_passwords=0

Reiniciar Mysql (Servidor)