Reboot while testing from bootable USB

[plkoij]

I'm testing 14.04 on a new laptop and want to test some changes that require rebooting. Is it possible to test these changes before actually installing the OS?

[sudodus]

Yes, but not with a standard live system. You need to make it a persistent live system with a casper-rw file or partition and the boot option persistent.

There are several links, see for example links from this tutorial page

Try Ubuntu (Kubuntu, Lubuntu, Xubuntu, ...) before installing it

and these links will help you do it automatically

https://help.ubuntu.com/community/In...as_usb-creator

'Stored in reserved extra space'

http://zleap.net/unetbootln-usb-how_to/

'Space used to preserve files across reboots'

Edit: But changes that involve the linux kernel will not work in persistent live systems. You can still test in a USB pendrive, but in such cases, make a full installation to a (second) pendrive, and test there before installing to the internal drive. An installed system will be very slow with a standard USB 2 pendrive. But it will be reasonably fast with a fast USB 3 pendrive even in a USB 2 port. See this link (post #6)

http://ubuntuforums.org/showthread.p...5#post12907085

[plkoij]

I think I've already done this; I chose the option in Startup Disk Creator to store documents and settings in reserved extra space, and there is a casper-rw file on the USB. But if I create a file and then reboot it disappears. Why would this be happening?

[sudodus]

Did you add the boot option persistent (either in real time (when booting) in the grub menu, or edited into the boot configuration file).

See this link One pendrive for all PC (Intel/AMD) computers

Edit the file syslinux/txt.cfg (in the FAT32 partition)

Add persistent like this:

from

append noprompt cdrom-detect/try-usb=true  file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz  quiet splash --

to

append noprompt cdrom-detect/try-usb=true  file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz  quiet splash persistent --

or if you want it ported to an installed system (if you are using the live system to install)

append noprompt cdrom-detect/try-usb=true  file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz  quiet splash -- persistent

[plkoij]

Thanks! syslinux/txt.cfg already had the persistent option, but I had to add it to boot/grub/grub.cfg, and it works now.

[sudodus]

Good catch

I see, you are booting from grub - I guess you are running in UEFI mode.