hacking boot options on live usb

[MichaelBurns]

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.

[AndrewSerk]

Hello,
You could setup your usb flash drive for multi boot, installing grub and then add :
hiddenmenu
timeout=0

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

[Teibidh]

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.

[AndrewSerk]

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