Casper 8 Startup Disc (Boot CD) Full Version
Kum Dana
With that out of the way: I've created an Ubuntu 14.04.03 Live USB Flash Drive (32GB) using UNetbootin, as well as the Ubuntu Startup Disk Creator. In both cases, I was able to successfully deploy my Ubuntu ISO (which I've confirmed is intact via md5sum analysis). In both cases, persistence worked successfully (I had to manually enable it when using Ubuntu Startup Disk Creator, but UNetBootin adds the -persistent kernel argument automatically to syslinux.cfg), no problems.
I need to have a persistence file larger than 4GB, as I'm creating a bunch of these flash drives for Field Application Engineers (FAEs), and they need to be able to use them on the road to diagnose installations for custom systems my company currently supports. It's fine if they burn out due to excessive write cycles, and each FAE gets a dozen of them if needed for each trip.
Also, we need to keep the first partition on the disk as a FAT partition in case the FAE needs to drop files onto the disk from Windows, Mac, Linux, etc, as Windows machines refuse to mount FAT partitions on a flash drive unless they are the first and only FAT partition on the disk.
I followed all of the advised steps, but booting fails. When I attempt to boot from my newly-created flash drive, I am directed to a prompt instead of Ubuntu properly booting, though I briefly see the graphical Ubuntu startup screen animation.
This time it at least finds the boot partition and starts attempting to boot the Live USB disk, but seems to fail along the way, with a bunch of "casper" related warnings. I can't seem to save those logs though, so I'm unable to provide them at this time. My current default kernel arguments are:
There is a work around recently updated in the thread for the bug, which I will elaborate on below as the other thread doesn't seem to have as much visibility (comes up lower in the google search when I was trying to work it out).
Use universal USB installer, etc to set up the OS partition with casper-rw file large enough to be able to make changes - needed for later step to workaround bug (I did it with 2gb, but surely it requires less)
mkusb works with some linux distros derived from Ubuntu too. I have not tested with the newest Linux Mint versions, but it works with previous versions because the boot structure is/was similar enough to Ubuntu.
I did have to make some details that may make Yu Jia's instructions a bit clearer. (Please note, these instructions may not be fully appropriate for default Ubuntu ISO image as I think some of the file locations may be altered by the Systemback configuration).
So - I copied this file to my 'casper-rw' partition, but then I realised that my GRUB boot menu looked was referencing /casper/initrd.gz (in four places) which resides within /boot/grub on the UUI partition.
Many thanks to all, and I hope my experience helps someone else!(Note - I'm a sufficiently new to Stack Exchange usage that I can't comment - hence my answer is new, rather than a comment on Yu Jia's).
My latest ISO image is something like 3.8 GB (it's a customised Ubuntu 16.04) and after three tries I have to create the initial OS partition at 5 GB and use a 1 GB persistence setting in the installer - otherwise you run out of storage when updating the initramfs functions.
Unallocated partition is added later in step3, sdc2 is for Ubuntu and sdc3 is for persistence. Since this is an 8GB pendrive, I used 3.32GB as persistent drive but will work with any size. Label this partition as casper-rw.
It's seems to be the booting process interrupted just after loading the initial RAM disk. This is due to the failure to mount the root file system (filesystem.squashfs). As everything works fine before editing the partition one or more of the following may be the reason for the failure.
I have been having a similar problem with the Lubuntu 14.04.3 i386 ISO image and gave up. I then tried the Lubuntu 15.04 AMD64 ISO image (I had earlier given up on 15.04 because of a bug that occurs at bootup, but it turns out to be only a small issue*).
The casper-rw partition works fine with the later system (following the usual instructions), so it seems the problem is nothing to do with process, but to do with a problem specific to some 14.04 ISO images.
I ask because I've recently copied the contents of an Ubuntu based live ISO (easypeasy, the ldistro for nwtbooks) onto a hard disk drive, but the Squashfs file system is corrupt, most likely because I copied it live. :) So it's not autologging in. Is there a username/password for this?
I'm not sure what the answer is, but I've solved this another way, so it's not a problem for me anymore. I discovered recently that it's possible to disable the password for an account. You can do this to force ssh key logins. I suspect that's what's going on here.
In the latest 22.04 versions of Ubuntu, the username is the same as the computer name. The password is blank. On ISOs that use the Ubiquity installer (Ubuntu, Kubuntu, Ubuntu Budgie, Xubuntu, and Ubuntu MATE), simply typing the username and pressing Enter will immediately log you on. For ISOs that use the Calamares installer (Lubuntu, Ubuntu Studio), you will be asked for a password - simply press Enter when that happens and you will be logged on.
Here I've copied the contents of the casper directory into a directory named /lucid32 on the root of a data partition. It's the UUID of the data partition that's added to GRUB's boot option. The option 'live-media-path=' tells casper, the Ubuntu live boot software, where to look for the filesystem image so you can create the directory by whatever name you like.
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