Luis,
of course all the single registrations on the hard disk are still there, but so are the block registrations (the ones stored in flash memory, that you call pressing "OO1", "002", etc.)
The weird thing is that my XD3 has more than 170 of those registrations, corresponding to the most commonly used styles, while this feature seems to be lacking in OS 4.0.
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Korg Kronos 61 and PA3X-Pro76, Roland G-70, BK7-m and Integra 7, Casio PX-5S, Fender Stratocaster with Fralin pickups, Fender Stratocaster with Kinman pickups, vintage Gibson SG standard.