Venturer sts 75e problem after unlock Region Code

Hello , I Have unlocked a venturer sts 75E with 8.1.3.2.8 and enter succesfully.

But now I Have the problem that most of the discs goes ¨Invalid disc¨ ,and only a few plays either Region 1.2.4.etc.

Can anyone help me??? Do any of you have face a similar problem?