08-18-2019 04:07 PM
I have been trying to boot ubunto from an external ssd but it doesnt seem to be working. I created a bootable flash drive with linux live, and used that to do a full install on an external ssd using this tutorial. But when I try to boot it from my thinkpad, the ssd is visible in my boot options, but everytime I click on it the screen turns black for a couple seconds, and I am returned to the boot menu. The bootable flash drive still works and I know ubuntu installed correctly on the ssd because I am able to boot it using an old dell laptop as well as my pc, the thinkpad is the only one that wont work(and the only one I even need it to work on). I have tried disabling secure boot, and using legacy boot instead of UEFI and experience the same issue. Any help is appreciated.
Solved! Go to Solution.
08-18-2019 06:12 PM - edited 08-18-2019 06:14 PM
HI, I boot Ubuntu (and other linux) from external usb media on a T480 and a P50 quite a lot.
Focusing on Ubuntu:
you want secure boot off (to keep it simple, in principle I think you can use secure boot, but I don't bother)
you want to use UEFI booting, and your existing installed operating system needs to use this. A modern Thinkpad will do this.
Do not use legacy boot if your first OS is not using legacy boot.
If you are using legacy boot, then you will have to get help from someone else.
There is an unfortunate bug in the ubuntu installer which may be biting you. Normally when you want to install Ubuntu on an external SSD, you want to have the machine boot from the SSD and therefore you want the Ubuntu boot loader on the SSD. This means you do not touch your existing internal HD at all. With this objective, you carefully tell the ubuntu installer to put the boot loader on the external SSD. However, you are ignored, it puts the boot loader on the first EFI partition it finds, which is the internal SSD.
Instructions to fix that are here:
https://askubuntu.com/a/1056079/152287 (that is, my answer).
Note: after doing this, you must activate the boot-time boot menu (F12 on my Thinkpads). You will see an option to change your boot device to the external drive you installed Ubuntu to. You must change to this boot device.