LINUX HOST -- GOOD RUNNING VM -- Cannot boot from iso file

[jcdole]

Hello
I have a good opensuse leap 15.2 running vm.
I want to boot that vm from an attached iso file (another version of opensuse install ).
Something like a real computer where a running linux system is installed and booting from a bootable usb stick.

When I start the vm, the f12 key has no action. I boot directly from the vdi.
The iso file is correct as I can create a new vm using it.
Any help is welcome.

[mpack]

I see that the VM is configured to use the EFI BIOS. With EFI the boot order is selected by the boot manager installed in the "system partition" on the primary drive. I don't know of any way to override that.

Had the VM been configured to use the legacy MBR BIOS then boot order can be configured in the VM settings (equivalent to MBR BIOS settings). You could perhaps do this as a temporary measure. Note however that the primary drive will still be using GPT partitions, so you need to bear that in mind if the software on the CD will attempt to access the primary drive.

[fth0]

When using the (U)EFI BIOS, you can press the ESC key very early to get into the (U)EFI Boot Manager.

[jcdole]

On a real computer you can change the uefi boot order by using the f1,f2,f8,esc (depending of the vendor) during power up.

My purpose is to upgrade or reinstall the OS on the same VM.

[scottgus1]

Those keys are programmed into the PC's BIOS. Thus you can't always use the same key for all PCs, since it's up to the BIOS writer which key to pick.

Virtualbox's key is ESC, as fth0 pointed out. Once that boot manager (black text on gray background, BIOS-style menu) is showing, you can select to boot from the VM's CD drive.

[jcdole]

OK, esc key do the job.

Thank you very much everybody.