>BTW, even the official document of Python2.4, chapter "7.3.2.1 Built-in
> Codecs", mentions that the:
>   PyObject* PyUnicode_DecodeUTF16( const char *s, int size, const char
> *errors, int *byteorder)
> can "switches according to all byte order marks (BOM) it finds in the
> input data. BOMs are not copied into the resulting Unicode string".  I
> don't know whether it is the BOM-less decoder we talked for long time.

This seems to be wrong. Looking at the source code (Objects/unicodeobjects.c) reveals that only the first BOM is skipped.