I'm trying to use the Gentoo minimal install CD (specifically install-amd64-minimal-20150910.iso, though that is unlikely to matter) to install my new Lenovo ThinkPad T450s.

I can boot off my USB CD-ROM or USB key by hitting enter to interrupt the normal boot, hitting F12 for the boot menu, then selecting my USB device, and the minimal CD boots up to the kernel selection menu. However, when I attempt to boot that kernel, I end up with a "Media not found" error when Gentoo tries to mount the root filesystem from the USB device.

I've tried both an external USB CD-ROM and a USB key, and both exhibit the same behaviour.

1 Answer 1


The culprit turned out to be USB 3.0! I was able to boot from the Gentoo CD by temporarily disabling USB 3.0 in my BIOS:

  1. Reboot the laptop and hit Enter to interrupt the boot process
  2. Hit F1 to enter setup
  3. Go to the Config tab and select USB
  4. Go to "USB 3.0 Mode", hit Enter, and select "Disabled"
  5. Hit F10 to save and exit
  6. When the laptop reboots, hit Enter to interrupt the boot process, F12 to enter the boot menu, then select your USB device
  7. When the SYSLINUX Gentoo boot menu appears, enter the following: gentoo slowusb scandelay and hit Enter

Everything should now proceed as normal.

Apologies for answering my own question, but I couldn't find anything with Google, and I wanted this info searchable in case someone else runs into this annoying issue. (It cost me an hour of my life to figure it out.)


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