Looks like you got an OEM drive that was part of a PC. As far as I remember 1.5* was mainly used in Packard Bell - but I could be wrong here.
There were two different hardware revisions of this drive and without a firmware dump, we cannot say which one you got. Perhaps you would be able to send this firmware to me? (eMail address in PM)
I think firmware 1.09, 1.0A and 1.0B should have support for both hardware revisions, so you probably best just stick to the latest version which is 1.0B