Apparently, only some of my readers have been able to derive the fix necessary to generate valid HDD passwords. It's been easily guessable that the prehashing scheme needed some minor modification. Before I get countless requests now, here's the C source code for hpgl's keygen:
You need a C compiler to generate the executable (d'uh), e.g. gcc/mingw32, Visual C, lcc, etc., or you can just use the binaries linked below.
Update: Windows binaries...