Hi Pylon,
yes i modified the variables declaration as:
byte volatile command = 0;
byte volatile txTable[4]; //for sending data over I2C
byte volatile rxTable[4]; //for sending data over I2C
bool volatile newDataAvailable;
ad some news here! Removing the check on command I get data on raspberry pi. Do you know why? But I get always [0,255,255,255]
but it is a step forward.