Mac rather than Linux, but never mind.
One of my users recently had his PowerBook fail, and needed to reinstall from an external source (as the DVD drive was broken). Apparently all the information he found online insisted that this could only be done via FireWire, either from an external DVD drive or by booting in Target mode (attached to another Mac). However, after some days of prodding at it, he eventually tried a USB external DVD drive, and that worked absolutely fine, albeit slowly.
While I’m on the subject, consider this a reminder to back your data up. I say this because my own laptop died last week (thankfully I did have a recent backup!). The Mac Target mode did come in handy here. My hard drive was showing errors when I booted verbosely (hold down Apple-V as you press the power button & hold it until the boot screen appears - may take some time). However, when I attached it to another Mac via FireWire, and booted it in Target mode (hold down Apple-T during boot), it (eventually…) showed up as a volume on the other Mac. This meant I was able to rescue the one really important file that hadn’t been backed up in its most recent version, as I’d been working on it that day. After which, sadly, it expired entirely. I do now have a lovely shiny new black MacBook (prioritising size over the increased power of the PowerBook - it’s a shame they no longer make 12″ PowerBooks) as a replacement.