I was using my laptop to run Debian Wheezy as a server from the built-in HDD. It would never let the HDD spin down, though, so I decided to try booting from a USB flash drive. I left the original install on the HDD alone, just in case I screwed up.
I managed to install Debian Wheezy to a 4GB USB flash from the Netinstall ISO, but I must have messed up somewhere because, to boot the Flash drive, I have to choose the HDD from the boot menu. If I choose the USB drive, it just does nothing. My machine is capable of USB booting (I've done it before), I've just screwed up somehow.
I guess what's happened is that I mucked up the GRUB bit of the install, so it changed the /boot partition (the original HDD install uses separate /boot and / partitions) of the HDD to point to the Flash drive.
Once the machine is booted to the USB flash drive everything works fine: I can spin down the HDD immediately after boot and it never wakes up. But now I'd like to use the HDD to store data, but first I'm going to have to fix this /boot mistake.
I do have a /boot directory at the root of my USB flash install, and it appears to contain the correct files:
config-3.2.0-4-amd64 initrd.img-3.2.0-4-amd64 System.map-3.2.0-4-amd64
grub lost+found vmlinuz-3.2.0-4-amd64
I checked in cfdisk, and there doesn't appear to be a partition flagged for "BOOT" on the USB flash drive, as there is on the HDD, though there is a partition with all the same characteristics as the /boot partition on the HDD:
HDD: sda1 Boot Primary ext2 254.81*
Flash:sdc1 Primary ext2 254.81*
I'm thinking that fixing this might be as simple as flagging the sdc1 partition for BOOT, but I'd hate to make a further mistake that screws up both my working installs.
Can someone advise?