Midi speed Problem with RASPI 3

Hi to you all and thanks for your help.
I'm trying to use a RASPI3 and I found a source of
the problem by running the litle code in the "The definitive guide to MIDI IN with Raspberry Pi's GPIO".
When I run it, I get no NOTE OFF, and found the the RASPI is constantly receiving messages (255).
I guess it's a Baud speed problem, or UART configuration for RASPI 3 that I missed ?
Help please
:-d
Thanks
Alex

I'm using a Pi 1 B with USB MIDI and I also get hanging notes from time to time (suggesting that Note Off messages are not received consistently).
I'm not sure if it's a baud rate issue though, as missing Note Off messages are more frequent than missing Note On messages.
Maybe there's a way to debug this over a telnet session?

A Pi1 is too slow for real time audio. Period.