On Wed, 30 Dec 2015, Oliver Lehmann wrote: > Command 91h did the trick. Issueing this once before any > read/write commands makes the drive finally work!
FYI, this is what ATA-2 has to say about this command: "Note: Previous ATA specifications were unclear about the error conditions that this command may indicate. Some implementations do not indicate any errors for this command even when the command fails. However, most of these implementations do fail media access commands if a valid CHS translation is not in effect." -- which is (the latter sentence, that is) obviously what you've been observing with your WD drive. Also: "A device shall support the CHS translation described in words 1, 3 and 6 of the IDENTIFY DEVICE information. Support of other CHS translations is optional." FWIW, and good luck with your project! Maciej