I install ubuntu in a mobile-harddisk. But can not boot. I use below method solved this issue.
1. please insert a U-disk setup: enter ubuntu, setup ubuntu repair.
2. run ubuntu repair will setup and repaie the ubuntu boot issue.
3. please config bios: UEFI -- add setup a selection. for ubuntu : selection shaxi.原文：https://www.cnblogs.com/widic/p/10993963.html