On HP-aCC:
Executing command "/command_with_bool true" causes crash of
the program.
On Linux-g++:
Only 1/0 as bool parameters are accepted, other possibilities
are refused (true, yes, etc.)

This modification of G4UIparameter.cc helps:
int G4UIparameter::
TypeCheck(G4String newValue)
{
    char type = toupper( parameterType );
    switch(type) {
        // ...skipped
        case 'B':
             // modified -> causes crash on HP-aCC
             //newValue.toUpper();
             if (  newValue == "Y" || newValue == "N"
                  ||newValue == "YES" || newValue == "NO"
                  ||newValue == "1"   || newValue == "0"
                  ||newValue == "T" || newValue == "F"
                  ||newValue == "TRUE" || newValue == "FALSE"
                  // added
                  || newValue == "y" || newValue == "n"
                  ||newValue == "yes" || newValue == "no"
                  ||newValue == "1"   || newValue == "0"
                  ||newValue == "t" || newValue == "f"
                  ||newValue == "true" || newValue == "false")
                  return 1;
             else {
             // ... skipped
}