x5l CF mod - ata error: -1

[fip]

I am attempting a CF mod of my x5l
(similar to http://anythingbutipod.com/forum/showpost.php?p=542017&postcount=47, same CF to ide adapter, newer version of the
same SD to CF converter)

I hit a "ata error: -1" (also OF gives HDD error, but I could live with that)
drive is functional through USB though, ...

should I compile a bootloader with special options?? as far as I can see from the ata driver code the error indicates a pretty basic failure somewhere (the ata hard resets take
a while before the error appears), but on the other hand the x5l with CF mod functions quite normally as USB drive...