[CentOS] Upgrading (?) from legacy boot to UEFI

Sat Aug 28 08:24:56 UTC 2021
Simon Matter <simon.matter at invoca.ch>

> On 27/08/21 10:51 pm, Rob Kampen wrote:
>> Unfortunately the server is remote and the CentOS7 USB device I left
>> plugged into the machine refuses to boot from UEFI mode. Thus a rescue
>> mode boot has not been possible.
> So i made a trip and replaced the USB stick with another one - CentOS7
>> I am unsure what file I need to point the UEFI bios disk manager setup
>> at, I have tried shim.efi and shimx84-centos.efi
>> The message I get is that linux16 and initrd16 cannot find their
>> files. The change to linuxefi and initrdefi also fail but the system
>> reboot happens before I can see what flashes on screen.
>> Is a USB based UEFI booted rescue mode the only way I can fix this?
> So I then rebooted - selected UEFI native boot and got into rescue mode
> - only problem is that the rescue system did not find a Linux system.
> Really weird as each of the four drives effectively have a complete
> centos7 system. No idea why it didn't start md raid and find the 6 raid1
> volumes.
> About to give this a miss and just live with legacy boot - this UEFI
> thing is just far too complicated. Looking on line at all the various
> blogs and questions it seems I am not alone in finding it far too
> complicated.

Don't worry, you're not alone. IMHO UEFI and GRUB2 and the whole Linux
startup procedure can be a real problem to handle and I guess most people
just give up earlier or later and simply use the installer to do the job.