Updating the bios on my X200 Tablet was surprisingly simple in Debian. Often, updating bios requires some sort of Windows or Dos boot disk and all kinds of machinations to make that happen. Lenovo provides an iso image to update the bios which alleviates some of these problems, but as the X series don't have built-in CDROM drives (and I don't have an ultrabay),

All you have to do is download the iso, install syslinux aptitude install syslinux, and configure grub to start memdisk and boot off of the iso. You can do this by copying the iso to your boot partition (cp 7wuj43uc.iso /boot/;), copying memdisk to the boot partition (cp /usr/lib/syslinux/memdisk /boot/;) and adding an entry to your grub.cfg like the following (putting it in /etc/grub.d/40_custom is probably the most reasonable):

menuentry "Thinkpad x200 BIOS Upgrade to 3.19" {
       insmod part_msdos
       insmod ext2
       set root='(hd0,msdos1)'
       linux16 /memdisk iso
       initrd16 /7wuj43uc.iso

Note that your configuration will be slightly different depending on whether you have a separate /boot partition (I do) or not.

Then you just need to boot the laptop, select the bios upgrade option in grub, and tell the program that you really do want to upgrade the bios and that you really do have a full battery and the laptop plugged into an AC adapter.

The major idea for this method came from ThinkWiki's entry.