On Thu, 19 Sep 2019, Jerry Geis wrote: > I installed my first UEFI disk yesterday. Seemed to go fine. CentOS 7.6 > x86_64 > I then took that disk "out" of that machine and put it another machine - it > seems to not even boot. > I put the original disk back in that machine and it boots fine. > > I put the UEFI disk back in the machine I built it on and it works fine. > They are similar machines either and i3 and i7. > > Shouldn't that work? Build a UEFI disk on machine A - move it to machine B? I think the issue is that the UEFI firmware doesn't know which UEFI boot loader to load. I think this should help: https://noobient.com/2017/09/27/fixing-the-efi-bootloader-on-centos-7/ Boot into rescue mode, and run: efibootmgr --create --label CentOS --disk /dev/sda1 --loader "\EFI\centos\shim.efi" I think you then should end up in a happy place. You can probably add that entry by hand within the UEFI config itself. HTH, jh