GRUB seems to have some difficulties operating in a dynamic environment (for example, when booting from removable media on different computers) <a href="http://en.wikipedia.org/wiki/Live_USB">when trying to boot an OS frmo the removeable media itself</a>.

<h3>Specific problems</h3>
<ul>
<li><a href="http://www.knoppix.net/forum/viewtopic.php?p=101767">hd0</a> varies with environment
<li>the <a href="http://www.gnu.org/software/grub/manual/html_node/Device-map.html">device map</a> varies with environment
</ul>

<h3>Specific solutions</h3>
<ul>
<li>grub's own facilities
    <ul>
    <li><a href="http://www.supergrubdisk.org/">Super Grub Disk</a> contains a modified version of GRUB v0.97 that includes the following extra features: (<a href="http://forjamari.linex.org/frs/?group_id=61&release_id=623#623">download SGD source code</a>, and diff versus the original GRUB code, to see the changes)
        <ul>
        <li>usbshift
                <a href="http://forums.hardwareguys.com/ikonboard.cgi?act=ST&f=12&t=5353&st=#entry37437">[1]</a>
                <a href="http://grub.enbug.org/AdrianGibanel">[2]</a>
        <li>setgrubdevice / $(grub_device)
                <a href="http://forums.hardwareguys.com/ikonboard.cgi?act=ST&f=12&t=6050&st=#entry42715">[1]</a>
            <!-- <ul>
            <li>requires a special patch (that Super Grub Disk has)?
                    <a href="https://listas.ensanjose.net/pipermail/supergrub/2007-September/000448.html">[1]</a>
                    <a href="http://www.supergrubdisk.org/forum/index.php?topic=71.0">[2]</a>
            </ul> -->
        <li>manually do `<a href="http://www.troubleshooters.com/linux/grub/grub.htm#_Having_Grub_Do_Your_Research_For_You">find</a>`, then manually enter that value into `grub_add` , then use that variable as part of each rule (HOW?)
            <ul>
            <li>`grub_add` is also a SGD patch, however, it just maps to the "set" command, <a href="http://grub.enbug.org/CommandList">which <i>is</i> available in stock GRUB</a>
            </ul>
        </ul>
    <li><a href="https://gna.org/projects/grub4dos/">grub4dos</a> contains a modified version of 
        <li><a href="http://www.knoppix.net/forum/viewtopic.php?p=95990">find --set-root</a>
        <li>cdrom --init
        <li>setvbe (set the video mode)
        <li>&amp;&amp; and || operators
        </ul>
    </ul>
<li>other bootloaders to replace grub, or to chainload from grub  (rule of thumb: use whatever <A href="http://en.wikipedia.org/wiki/Live_USB#Examples">the other LiveUSB distros use</a>):
    <ul>
    <li>syslinux 
        <a href="http://www.gnu.org/software/grub/manual/html_node/Device-map.html">[1]</a>
        <a href="http://www.knoppix.net/forum/viewtopic.php?p=101767">[2]</a>
    <li><a href="http://gentoo-wiki.com/GRUB/Chainloaded_CD-ROM">Smart Boot Manager</a>
    </ul>
<li>give booted OS's enough information to find the right partition
    <ul>
    <li><a href="http://www.unixtutorial.org/2008/05/ubuntu-uuid-how-to/">use UUIDs</a>
    <li><a href="http://www.linuxtalkz.com/9599-post3.html">use root=label=[partition_label]</a>
    </ul>
<li>don't know how to classify
    <ul>
    <li><a href="http://grub4dos.sourceforge.net/wiki/index.php/Grub4dos_tutorial#Difference_between_GRUB_for_DOS_and_GNU_GRUB">grub4dos's grldr</a>
    </ul>
</ul>