How about this, from https://support.hp.com/us-en/document/c03840403

== To get more information while booting
Press F10 during boot to access BIOS (as I think you've been doing)
Disable Quick Boot (Always Full Boot)
Enable Post Messages

Reboot
Press Esc (I generally press it once a second until something happens)
That should access the boot menu, with a list of bootable devices.

Note the URL above states:
"note: To drag a device to a preferred place, press Enter. To remove the
device from consideration as a bootable device, press F5. F5 can be used
to disable individual boot items, as well as disable EFI boot and/or
legacy boot."
so, theoretically, you can change to boot from legacy there, though that
will probably revert on the next boot.

If your USB does not display in legacy all the time, go back into BIOS.
Futz around until you find the place where you can turn the boot into
legacy (turning off EFI), then reboot and press Esc.

Secure boot is a Microsoft pushed thing, but it is not only applicable
to Windows. However, it is definitely unnecessary for Linux, I'm pretty
sure. I have turned it off several times on workstations.

Rod


On 1/3/23 19:38, Fred wrote:
> On 1/3/23 18:22, john faulk wrote:
>> Have you tried going into the bios at all?
>
> Yes, I have been all through the bios.  I checked the boot order which is:
> CD (which the pc doesn't have)
> USB
> Network  (which I removed)
>
> There is another page that also lists the internal hard drive.
>
> The boot options are: Legacy and Secure Boot which appears to be a
> Windows thing.  There is a tab for UEFI drivers.  If that is selected it
> changes to a page that says I will be directed to a page for a third
> party rom also accessible  with F3.  If that is selected it changes to a
> page with only the option: EXIT which reboots the pc.  I assume the rom
> is not installed.
>
> Best regards,
> Fred
>
>>
>> On Tue, Jan 3, 2023, 7:18 PM Fred <fred@???
>> <mailto:fred@blakemfg.com>> wrote:
>>
>>     On 1/3/23 15:54, Antony Stone wrote:
>>      > On Tuesday 03 January 2023 at 22:28:41, Fred wrote:
>>      >
>>      >> Hello,
>>      >>
>>      >> I bought a "refurbished" HP EliteDesk 800 G2 mini-pc with the
>>     intention
>>      >> of running Chimaera on it.  However, it will only legacy boot
>>     and the
>>      >> .iso install files for Chimaera on the USB stick are .efi.  Is
>>     all hope
>>      >> lost or is there a work around?
>>      >
>>      > Sorry, but I don't understand the problem.
>>      >
>>      > I have at least four machines here which have no concept of UEFI
>>     - they boot
>>      > using BIOS only, and yet they (start and) run Chimaera quite
>> happily.
>>      >
>>      > So, when you attempt to install Chimaera on this EliteDesk
>>     machine, what
>>      > exactly is the problem you run into?
>>      >
>>      >
>>      > Antony.
>>      >
>>     The pc sees the usb stick as it turns on the led and at times
>> makes it
>>     flash.  However, what it does is snoop around the local network
>>     until it
>>     finds the gateway then it downloads Windows 10 and starts setup for
>>     that.  If I don't have the Ethernet cable attached it eventually
>> brings
>>     up a screen with several remote servers and allows one to be selected
>>     but it won't continue without the network.
>>
>>     I used dd to write this file:
>>
>>     devuan_chimaera_4.0.0_amd64_server.iso
>>
>>     to the usb stick.  I can mount it and see the files:
>>
>>     There is: /efi/boot/bootia32.efi
>>     and:      /efi/boot/bootx64.efi
>>
>>     What can I check now?
>>
>>     Best regards,
>>     Fred
>>
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>>
>
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