7551 flash Slave to Master?

I have flashed my 7551 with the nec reverse ATA firmware http://www.de.nec.de/faq_detail.php/id/1350/frage/687/lang/ENG cause of problems with original CD’s.
Now I am sure the problem doesn’t depend on Master or Slave settings cause my HP pavilion (DV4000) didn’t work with the Slave drive. When i put the drive in an desktop PC everything is fine. Does anyone know, how to flash the drive as Master again?

I made a master package for this drive, but the batch scripts still aren’t working the way they should. I need to do some testing, but I don’t have time for that during the next days/weeks.