Lenovo M600 BIOS update without Windows (en)

Some time ago I picked up a mini-PC as a bargain for 25 €, which I use from time to time for experiments. The device has a Celeron N3010 at 1 GHz, so it’s at the lower limit for using a Linux desktop. Windows definitely isn’t fun on this little box.

But with 4 or 8 GB of RAM (in a SODIMM format like a laptop) and an SSD (unfortunately only SATA, no M.2) the little box is tolerable for a small home‐server for automation or as a Pi-Hole for global ad-blocking — after all it doesn’t always have to be a Raspberry Pi :-)

At some point I happened to notice that on the Lenovo website there is a BIOS update. My PC had version 50, and I could update to version 68A. As an old update-junkie I naturally have to actually do this :-)

Well, the update is offered as a Windows file, so I would need Windows on the PC. As alternatives there is an ISO file and a file that works under FreeDOS. Read that right: there are enthusiasts who maintain DOS, and FreeDOS is a free variant of MS-DOS, even with network support, and in the “full” variant there are also apps, including even GNU’s wget.

The ISO file can be written to a USB stick under Linux using the command dd. That option didn’t work for me; the USB stick refused to boot.

The other option then was to create a USB stick with FreeDOS. That too didn’t work at first, but for a different reason: I had first downloaded a trial image of FreeDOS that works with a boot diskette in a RAM‐disk and doesn’t let the USB stick be visible from within DOS. I had copied the Lenovo files onto the USB stick, but with that FreeDOS I could not access the USB stick. So another attempt …

The solution: Download the Install file for FreeDOS (full or lite version makes no difference), create a USB stick with it (again with dd), and then copy the files from Lenovo for the BIOS update onto the USB stick (of course adjust /dev/sdb as your device!).

unzip FD14-LiteUSB.zip
dd if=FD14LITE.img of=/dev/sdb status=progress bs=4M
mkdir -p /mnt/usb
mount /dev/sdb1 /mnt/usb
unzip m00jt68usa.zip -d /mnt/usb/m600

With this bootable USB stick you can then update the BIOS. Plug the USB stick into the PC and immediately after switching on, while “Lenovo” is displayed, press F12 so that the boot-device selection options appear. Lenovo recommends resetting all settings in the BIOS to “Default” before the update. Also you should check that “Legacy Boot” with the “CSM” is turned on, otherwise the USB stick will not be displayed in the boot menu.

After booting the PC looks like 40 years ago with a DOS prompt in text mode.

cd m600
autoexec.bat