Fedora Linux Support Community & Resources Center
Old 16th December 2010, 08:00 PM
MichaelBurns Offline
Registered User
Join Date: Dec 2010
Posts: 19
hacking boot options on live usb

I would like to find out how I can hack into the iso file to change the boot options (esp.: automatic boot without 10 sec delay, persistence, read/write mode). Where can I find documentation for this? Or, anyone who would be so kind is more than welcome to just help me here in this thread.

I just dd'ed the iso onto my usb stick:
dd if=/path/to/Fedora.iso of=/dev/sda
(i.e. directly to the device, not to any partition on it). It seems to work just like I would expect the live CD to, which unfortunately means read-only. This is the main feature that I want to change.

What I'm worried about is: do I need to make any special provisions so that certain sectors stay put, or can I just edit files and let the file manager worry about what sectors to put them in? I'm assumig that there is some compressed file system or something. I don't know which files that I should edit or how; I'm assuming some isolinux files. I've been reading about it for months, but the boot process is still a bit baffling to me.
Reply With Quote
Old 17th December 2010, 10:30 PM
AndrewSerk Offline
Registered User
Join Date: Oct 2010
Posts: 894
Re: hacking boot options on live usb

You could setup your usb flash drive for multi boot, installing grub and then add :

at the top of grub.conf . If you install one cd img you can use the other partition for storage

dnmouse has a great tutorial on the subject: http://dnmouse.org/forum/viewtopic.p...8f5d754eae8887
Reply With Quote
Old 7th March 2011, 02:44 PM
Teibidh Offline
Registered User
Join Date: Nov 2010
Posts: 16
Re: hacking boot options on live usb

I don't know the commands off the top of my head, at least, not the syntax for them. But, you can edit the stuff without too much trouble. The trick is using unsquashfs to decompress the live-usb file system, make your changes, then us squashfs to put it back together. The only thing that hinges upon being on a certain sector is the boot record which shouldn't be modified by this.

Edit: You can also edit a couple of the files in the isolinux folder on your flash drive to modify the boot behavior without having to mess with the rest of it, you should find the automatic start delay and the quiet settings there at the least, and I'm fairly sure you can specify 'rw' on the kernel command line in these files as well.
Reply With Quote
Old 22nd March 2011, 06:25 AM
AndrewSerk Offline
Registered User
Join Date: Oct 2010
Posts: 894
Re: hacking boot options on live usb

When you get to the countdown screen press any key, then press the Tab button. That should bring up the default boot parameters from a livecd and you can add parameters there.
The parameters that I know of are:
* automount: enable automounting of all found harddisks
* noswap: do use local SWAP partition
* pw=any_password: set a password for root and local user
* user=username: user name of local user, default is sluser
* noautologin: disable auto login
* cell=your.cell: set an AFS cell (however, afs client is not installed per default)
* cups=server: set a CUPS server
* serviceon=s1[:s2:..]: enable the service(s) s1,s2,... (e.g. serviceon=ntpd:smartd)
* serviceoff=s1[:s2:..]: disable the service(s) s1,s2,... (e.g. serviceoff=netfs:xinetd)
* hostname=...: define hostname
* changes=any_foldername or changes=/dev/sda2.... to specify persistent changes partition or directory

* rdinitdebug: debug dracut boot process. Debug output will be displayed by dmesg command
* overlay=UUID=: defines the UUID of the USB device used for persistent overlay
* liveinst: Will directly start graphical installation to hard drive
* textinst: Will directly start text based installation to hard drive
* check: Will check the LiveCD checksu
* kb=us: to set a keyboard layout (or keyboard=...)

If the LiveCD hangs during booting, try to boot with one or more of the following boot parameters:

* apm=off acpi=off noapic noswap nomodeset all_generic_ide pci=nommconf

Last edited by AndrewSerk; 22nd March 2011 at 06:45 AM.
Reply With Quote

boot, hacking, live, options, usb

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Live CD Hangs not matter what boot options I choose kc0rpm Installation, Upgrades and Live Media 0 9th February 2010 12:17 AM
Boot F11 Live CD - Mount F11 Live USB bootspooge Installation, Upgrades and Live Media 1 20th October 2009 06:43 PM
What live cd and boot options need for i7 with 12gbs of ram?? :) locustmage Installation, Upgrades and Live Media 6 11th April 2009 02:30 AM
Too many boot options Keige Installation, Upgrades and Live Media 10 9th January 2005 12:43 PM

Current GMT-time: 05:42 (Saturday, 23-09-2017)

TopSubscribe to XML RSS for all Threads in all ForumsFedoraForumDotOrg Archive

All trademarks, and forum posts in this site are property of their respective owner(s).
FedoraForum.org is privately owned and is not directly sponsored by the Fedora Project or Red Hat, Inc.

Privacy Policy | Term of Use | Posting Guidelines | Archive | Contact Us | Founding Members

Powered by vBulletin® Copyright ©2000 - 2012, vBulletin Solutions, Inc.

FedoraForum is Powered by RedHat