Raspbian, external USB hard drive, reboot fails.

Hi group,

I have just reinstalled my Raspbian OS on an external USB hard drive because of many failed SD cards. Now when I reboot, it fails because the hard drive powers down and stays down. I need to power down completely before the machine will restart. I am using an external power supply for the hard drive and the Pi. Looking at using a 555 chip with a relay but not sure how to trigger the circuit?

Has anyone else seen this problem and what did you do to work around it?

This post looks like it has some ideas

Yes hdparm is he way to do this. Can make things a tad unstable, when the OS tries to access the hard disk, and it needs to spin up first, things time out. There are various flags you can pass, -y -Y -s -S, read the man page. Not all hard drive take all options - but you might as well try. Usually some work.