err...can I get that PM?PM sent.
Actually, I have legit Cobra HDD and its dongle, but when I tested sd2psx COH dongle files, I might have mistakenly chosen other version, and as a result, my legit HDD looks locked.
After I faced the following error during sd2psx dongle test which I have never experienced before.Harddrives will not stop working from using wrong dongles.
Understood.I find it more likely that the system settings stored on the motherboard are somehow now incorrect, and that is stopping it from booting. As far as I know nothing is written on the HDD, so you cannot brick it.
Try booting a completely different game in between. That will initialize the settings.
Also, if you're going to image the Mame chd on a drive, do it on a different drive, not the original drive. Your original drive could contain a different version.