You will need:

• Ubuntu (live CD may work, haven't tested) I used 9.04 and assume you do too
• a blank usb stick, a small one is fine
• an internet connection

First:install hfsplus and hfsprogs with apt-get or synaptic

insert your usb stick
open a terminal, sudo -s then type df to check where it is & where it's mounted, note the position & unmount the stick.

(I will use /dev/sdb as the example device and LinOSX as the volume label & mount point for the usb stick, substitute your own values)

Use

CODE

fdisk /dev/sdb

to remove whatever partitions you have and create a new primary partition, type AF, active.

Use mkfs.hfsplus to make a new hfs+ filesystem on your new partition. I used:

which sets the volume name to LinOSX and the user & group to 0:0

Next we install the chameleon bootloader:
download & unpack the latest chameleon binary package, in this case Chameleon2.0RC1-r431
cd to the i386 directory inside, and, making sure that /dev/sdb1 is unmounted, do:


next we mount the stick, I used:

then, true to a long tradition, I typed:

to check for writeability.

All being well you should now be able to write to this drive *but only as root* so,

and now cp the contents of "Optional Extras" into the Extra folder you just created

The stick needs a decryptor, I chose Appledecrypt, google for it, download, and drop Appledecrypt.kext into Extra/Extensions with cp -R, kexts are folders in linux.
a Disabler.kext might be useful, same procedure.
when you have all the kexts you think you'll need to boot, check the ownerships are root:root on all the kexts (they should be) and if necessary


You're done!
sometimes the stick refuses to mount readwrite, after being mounted on OS X, try fsck'ing it

The booter doesn't care about the owner, group and mode of the files and directories, it's probably only needed if you plan to pack them in an Extensions.mkext.

Nice guide!

That's really interesting, as the inability to set permissions is the main reason I gave up on the windows method, I may try it again.

Cool guide, Hagar, it's always nice to know you can bootstrap OS X from Linux.

While It's good to know from Kabyl that the booter does not care about permissions, I think it's never too early to teach n00bs, how to deal with KEXTs.
If you download KEXTs from a reliable source, hopes are high that they have proper permissions set, and Linux is going to preserve those if you ask it to.
Therefore, I prefer to use "cp -a" over "cp -R" because the former maintains all permissions and other metadata of the files. The "-a" flag does not work under OS X though, where you need to use "cp -pR" to achieve the same.
To set proper permissions on the KEXTs, the commands I use are

The above chmod command (with "go=u-w" instead of "755") sets the permissions of group and others to be the same as those of the user (=owner) but minus write permissions. This has the advantage of only leaving the executable bit set on items that already have it, avoiding to make all files executable. Having the wrong files executable is a security risk. And since it's no extra typing effort, we might as well teach the n00bs to use this from the beginning :-)

Also, for the record, if anyone wants to prepare the USB stick under OS X, be sure to enable ownership and permissions after formatting it, as otherwise, none of the chown and chmod commands have any effect. From Terminal, you issue

Or go to Finder, do a right click on the volume and choose "Get Info"; then disable "Ignore ownership on this volume"; it's at the very bottom and you may need to click the padlock and enter your admin password first.