[id='troubleshooting_live_USB']
= Troubleshooting a live USB


== livecd-iso-to-disk problems

Partition isn't marked bootable:: If you get the message `Partition isn't marked bootable!`, you need to mark the partition bootable. To do this, run `parted /dev/sdX`, and use the `toggle N` boot command, where `_X_` is the appropriate letter, and `_N_` is the partition number. For example:
+
[source,shell,subs="attributes"]
----
$ parted /dev/sdb
GNU Parted 1.8.6
Using /dev/sdb
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print
Model: Imation Flash Drive (scsi)
Disk /dev/sdX: 1062MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      32.3kB  1062MB  1062MB  primary  fat16

(parted) toggle 1 boot
(parted) print
Model: Imation Flash Drive (scsi)
Disk /dev/sdX: 1062MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
 1      32.3kB  1062MB  1062MB  primary  fat16        boot 

(parted) quit
Information: Don't forget to update /etc/fstab, if necessary.
----

Partitions need a filesystem label:: If you get the message `Need to have a filesystem label` or `UUID` for your USB device, you need to label the partition: `dosfslabel /dev/sdX LIVE`.

Partition has different physical/logical endings:: If you get this message from fdisk, you may need to reformat the flash drive when writing the image, by passing `--format` when writing the stick. 

MBR appears to be blank:: If your test boot reports a corrupted boot sector, or you get the message `MBR appears to be blank.`, you need to install or reset the master boot record (MBR), by passing `--reset-mbr` when writing the stick.

livecd-iso-to-disk on other Linux distributions:: `livecd-iso-to-disk` is not meant to be run from a non-Fedora system. Even if it happens to run and write a stick apparently successfully from some other distribution, the stick may well fail to boot. Use of `livecd-iso-to-disk` on any distribution other than Fedora is unsupported and not expected to work: please use an alternative method, such as link:#using-fedora-media-writer[Fedora Media Writer].


== Testing a USB stick using qemu

You can test your stick using QEMU.

[options="nowrap"]
----
# umount /dev/sdX1
$ qemu -hda /dev/sdX -m 1024 -vga std
----


== Mounting a Live USB filesystem

You can use the https://github.com/livecd-tools/livecd-tools/blob/master/tools/liveimage-mount[liveimage-mount] script in the https://apps.fedoraproject.org/packages/livecd-tools[livecd-tools] package to mount an attached Live USB device or other LiveOS image, such as an ISO or Live CD. This is convenient when you want to copy in or out some file from the LiveOS filesystem on a Live USB, or just examine the files in a Live ISO or Live CD.
