no boot from main drive

[anika123]

Thanks tlarkin for the replies and everyone else for the eyeballs.

It is fixed! The solution turned out to be that a re-partitioning was needed. It was the last thing I tried but worked fine. Time machine really turned out to be nice in this case. I was able to fresh install SL and then the 10.6.1 combo updater and then use Migration Assistant and Time Machine to put everything back exactly as it was.

I actually think disk utility may be a little at fault for the whole mess. Here is the story. The day before I had been re-partitioning an external drive and had to do it a few times for various reasons. This somehow re-wrote the partition map (i guess) of the internal drives and screwed things up. If I compare the above df output from yesterday to the one I get today, I see that the /dev/disk1s2 got translated to /dev/disk0s2. This apparently did not work so good. I guess this is why it kept booting the DVD image I had on the first partition of the second drive.

I think this is partly because I have two hard drives installed on my old mbp and the os occasionally gets confused. I had a similiar problem with Softraid on the computer. For some reason the original drive always appears to the system (internally) as the second drive and the old dvd slot as the first hard drive. Where on the outside, ie disk utility always reports it as the other way round.