PLi 8.1 and Multiboot

I have a VU+ Duo2 . I installed PLi8.1 It works perfectly, but I have some problem with Multiboot. I copy in the folder

open-multiboot-upload ..... openBH (in short. obh-5 )

Installed, but when I do a re-boot ... He show a first picture with OBH than change in the usual picture Poi 8.1 and start with PLi.

Somebody can help me?

Thanks