Bootable USB Not Working

Support & Help Requests
1

I'm trying to install Ubuntu 15.10 Mate onto a USB drive that will boot with Ubuntu running as the operating system (in a persistent way, not as a live demo). That way i can keep my work files on both my main computer's HDD and on the USB drive...and just take the USB with me when i need to work out of town.

First, I formatted the USB by doing the following...

I got the usb dev name:
sudo fdisk -l

I unmounted the usb:
sudo umount /dev/sd@

I formatted usb as FAT32:
mkdosfs -F 32 -I /dev/sd@

Then i used UNetbootin to create a startup USB using the Ubuntu 15.10 Mate .iso file on my main computer (HDD).

After UNetbootin ran it said that all was done correctly and that i just needed to reboot the system. I have my system set up so that it first tries to boot from the USB drive...but when i rebooted the only options that i had were to run 'Live' Ubuntu from the USB drive OR to install Ubuntu from the USB drive to my main computer (HDD).

Currently my USB drive looks like this...

Disk /dev/sdb: 111.8 GiB, 120034123776 bytes, 234441648 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 33553920 bytes
Disklabel type: dos
Disk identifier: 0x20ac7dda

Device Boot Start End Sectors Size Id Type
/dev/sdb1 3224498923 3657370039 432871117 206.4G 7 HPFS/NTFS/exFAT
/dev/sdb2 3272020941 5225480974 1953460034 931.5G 16 Hidden FAT16
/dev/sdb3 0 0 0 0B 6f unknown
/dev/sdb4 50200576 974536369 924335794 440.8G 0 Empty

Prior to using UNetbootin i tried to install the operating system via the dd command like this...

sudo dd if=/mypath/myisofile.iso of=/dev/sdb
...with the same results.

What am i doing wrong?

2

Perhaps up to this point you haven’t done anything wrong; there’s more to the process.

This might help

or this

3

After using “dd” you need to type the command “sync”.
It’s also possible, though it’s rare, that your USB key just can not be booted.

Now if I understand you correctly, you want the system to be installed on the USB, and not just having a live USB.

To do this, you need two USB keys.
The first to boot the iso you’ve flashed using the dd command, the second to serve as target for the installation.
Make sure your target key is large enough as per the minimum requirements.
Cheers

4

The live demo is persistent if you set up that way. What your describing is a full install. This is still possible on a USB. Boot your live demo and click install. You’ll of course need another USB to install it on and pay careful attention to your partitions but it can be done.