Updating a ThinkPad BIOS usually involves booting a floppy or CD-ROM containing PC-DOS and an update program, or running a Windows-only updater. Neither of these is an option on a machine like my ThinkPad X200s, which has no floppy or CD drives, and is running Linux only.
First, I downloaded the latest CD-based BIOS updater from the link
on the ThinkWiki BIOS Upgrade Downloads page.
In the case of the X200s, the bootable CD updater file was called
and was found here.
Then I logged in as root (using
sudo su) and performed the following steps:
apt-get install grub-imageboot cp 6duj48us.iso /boot/images update-grub
After rebooting, I realized that I needed to force the Grub menu to appear at boot time. (The menu
was invisible because this machine had no other operating systems
when I installed Mint. If your machine dual boots Windows and Linux with Grub, you
should not have to perform these steps.) As root, I edited the file
and commented out the line containing
GRUB_HIDDEN_TIMEOUT so that it looked
Finally, I ran
update-grub and rebooted. This time the Grub menu appeared,
and I was able to select
6duj48us.iso for booting.