ReBoot on iso file

[Thomas_06370]

Hi everybody,
I'm new here but I checked the forum and didn't find anything relevant to my problem. And apologies for my English, luckily for youn you don't have to hear me....

I'm using virtualbox for the sport/fun

Long time ago I created a VM on my Ubuntu desktop containing a CentOS7. Today for complex and out of scope reasons, I want to boot this very same VM on a iso file. The iso file is good, if I create a new VM it will launch it. But for unknown reason this VM with a CentOS doen't boot on it.
I properly attached the iso to a optical drive and change the boot order to start by it. I even unchecked the hard disk from the boot menu. Still the VM properly start on the CentOS, ignoring the fact I want to boot on a iso file ! I tried to check the "liveCd" option, didn't change anything.

By the way, the EFI option is set (I need it)

Please advise.
Thanks in advance for your help

VirtualBox Version 6.1.26_Ubuntu r145957


(nb: I read topic N° 5561 but didn't help. The F12 doesn't seems to be taken into account)

[mpack]

I'm not sure you understand what an ISO file is.

An ISO file is an image of a data CD/DVD/Blu-Ray. Period. If you have an image of a hard disk then it isn't an ISO image, because the name itself comes from the ISO-9660 filesystem on a data CD, and that filesystem is most definitely not used by any hard disk. A non-ISO disk image cannot be used in the CD/DVD/BluRay drive of any PC, virtual or not.

You need special tools in order to create a bootable ISO. Imaging the hard disk of a PC (or VM) will not do the job.

And btw, controlling the boot order in an EFI VM is a separate question. The old boot order VM settings only apply to MBR based systems. EFI systems seem to need a boot manager in order to function, and it's the boot manager that selects the boot device.

[scottgus1]

I actually think that you are trying to boot a existing working VM from an ISO, in the same way one might boot a working computer that already has an OS on it from a bootable CD a la the way Ubuntu lets one try Ubuntu from a LiveCD without overwriting the computer's existing OS.

If this is an accurate interpretation, your problem is as Mpack said in the last paragraph of his post: Your VM which boots from EFI no longer pays attention to the F12 key boot menu, which only applies to Virtualbox's Legacy BIOS.

You have to hold down or repeatedly type the ESC key while the VM is booting, then you can get to the black-on-gray EFI boot menu, where you can pick to boot from whatever is in the VM's CD drive.

[Thomas_06370]

Yeah thanks a lot, the ESC key, simple as that !
I hate myself for not founded it by myself, I was so deeply in the others solutions I found on Internet I forgot to think by myself.

Again, thanks a lot