Why do you need UEFI? It does not add to security "a lot" but was designed to block booting software like a "hypervisor". I used my Dell notebooks to test our hypervisor identification software (HyperCatcher if you are interested) which is bootable image. However, I was unable to boot it until I disabled UEFI. As I understand it, it will block anything from booting excepting original OS. Your Xen and our HyperCatcher are outsiders for UEFI. Mikhail Utin ________________________________ From: CentOS <centos-bounces at centos.org> on behalf of John Naggets <hostingnuggets at gmail.com> Sent: Tuesday, January 30, 2018 17:23 To: centos at centos.org Subject: [CentOS] Xen hypervisor on CentOS 7.4 with modern UEFI server not booting from grub Hi, I installed CentOS 7.4 on a modern Lenovo ThinkSystem SR630 server which uses UEFI. So far so good CentOS 7.4 works fine so then I went on to install the Xen hypervisor by following the instructions from the wiki (https://wiki.centos.org/HowTos/Xen/Xen4QuickStart). HowTos/Xen/Xen4QuickStart - CentOS Wiki<https://wiki.centos.org/HowTos/Xen/Xen4QuickStart> wiki.centos.org Scope. This guide will help you get from a baseline CentOS/x86_64 install to running the complete Xen-4 stack in just under 10 minutes, this includes getting your ... Unfortunately when I reboot after having installed the xen package the system does not boot into "CentOS Linux, with Xen hypervisor" from the grub menu prompt. I get the following error: Loading Xen 4.6.6-8.el7 ... error: can't find command `multiboot'. Loading Linux 4.9.75-29.el7.x86_64 ... error: can't find command `module'. Loading initial ramdisk ... error: can't find command `module'. Press any key to continue... The problem which I encounter here is exactly the same issue as described for Fedora in the RedHat bugs: https://bugzilla.redhat.com/show_bug.cgi?id=1286317 with the exception With 4.5.2 Xen update, the system no longer boot - Red Hat<https://bugzilla.redhat.com/show_bug.cgi?id=1286317> bugzilla.redhat.com Red Hat Bugzilla – Bug 1286317. With 4.5.2 Xen update, the system no longer boot. Last modified: 2017-08-08 19:49:12 EDT that for me it's CentOS 7.4 and that the workarounds as described in that bug do not work. Does anyone know how I can make my CentOS boot with the Xen hypervisor using UEFI? Thank you very much for your help. Best regards, John _______________________________________________ CentOS mailing list CentOS at centos.org https://lists.centos.org/mailman/listinfo/centos CentOS Info Page<https://lists.centos.org/mailman/listinfo/centos> lists.centos.org This is a General discussion list for all issues CentOS. Security updates are currently announced on this list once daily. This list is read and reply for anyone that ...