This question already has an answer here:
I'm trying to install the minimal Ubuntu installation on a USB drive (complete install, not a live boot). After installation, however, when I try to boot from the USB, I get "Missing operating system".
I think there might be a problem with
grub, but I don't know how to fix it. I've done an install to an USB before which messed up the main
grub file, so I don't want to do that.
This is the output of
fdisk -l pertaining to the USB drive:
Disk /dev/sdc: 4027 MB, 4027580416 bytes 124 heads, 62 sectors/track, 1023 cylinders, total 7866368 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x73a571aa Device Boot Start End Blocks Id System /dev/sdc1 2048 7616511 3807232 83 Linux /dev/sdc2 7618558 7864319 122881 5 Extended /dev/sdc5 7618560 7864319 122880 82 Linux swap / Solaris
Also, my boot partition may not be labeled as bootable, based on this output. Please help!
Terrance's suggestion, so /dev/sdc1 is now labeled as a boot partition. However, the drive still won't boot.
I am not asking for how to install Ubuntu to a USB drive, I'm asking for help fixing a USB which I've already installed Ubuntu to.
Terrance's updated answer solved it for me. Just a note, to get it working on my USB I had to create a
/boot/extlinux/syslinux.cfg file containing:
PROMPT 0 TIMEOUT 50 DEFAULT arch LABEL arch LINUX ../vmlinuz-4.4.0-45-generic APPEND root=UUID=[The USB UUID] INITRD ../initrd.img-4.4.0-45-generic