No, redo your partitioning completely.

You are using oldfashioned MBR legacy partitioning. That is causing problems. Start with creating a GPT partition table.

Then create the ESP, and then the other stuff as you like.

Such an option isn't there with reason. The ESP has to be a FAT32 partition on its own and will be mounted to /boot/efi. And per default it is never formatted or overwritten to save previous boot loaders for other OSes on the disk (multiboot).

How far out is that? Outside the 2T border?

Memory stick or hard drive on your Optiplex? You should use GPT on the target drive for an efi installation.

The first partition on the target drive should be the ESP, FAT32 formatted, I do recommend at least 512M, better 1024M. If you use manual partitioning, make sure its mounted to /boot/efi and used as ESP. Essential to successfully install grub.

Sort of:

* Boot your installation stick in efi mode.
* Select the Rescue Mode. You will get asked some basic questions about language, keyboard, network like during installation. Make sure you give similar answers. You will need internet access.
* The Rescue Mode should be able to detect the existing installation, and offer amongst other options a chroot into the installed system. Select that option.
* Edit the /etc/apt/sources.list to read something similar like: deb http://deb.devuan.org/merged/ daedalus main contrib non-free non-free-firmware.
* Run an apt update.
* Then run an apt install firmware-amd-graphics.

This should be it. Leave the installer and let the system reboot. I hope that fixes the black screen.

Welcome to Devuan.

Maybe that is part of the problem. I have used Rufus myself many years ago, nowadays I use Linux tools like dd or cp. Lets see if we can find the root cause.

Please tell us how you have setup your partitioning?

Yes that is done during executing grub-install on the end of the installation. If you don't skip that step. And only if you have started the installation in efi mode.

Well, the efi grub-install creates a directory /boot/efi/EFI/debian. And per default shimx64.efi is used as starter. But only if present.

Dual boot?

There is a thread where somebody else has issues with efi installation also. Please have a read, there is a lot of information in there that might help you too: https://dev1galaxy.org/viewtopic.php?id=6788

In any case, have you started the installation in efi mode?

Me myself never had such an experience. There shouldn't be any difference in graphics for the installer between legacy and efi mode.

Looking at mainboard and CPU, both are somewhat older and should be mature, i.e. any installation should be a nobrainer without difficulty.

Well, on the other hand, there is one newer bios available if I am not mistaken. I would load that in any case.

Then reset the bios to defaults, and switch off secure boot. Then give it another try, first of all boot a live cd in efi mode, then with the netinstall also booted in efi mode.

Yes, thats the typical symptoms of a legacy installation on an Uefi motherboard.

When you boot your installation stick, you will find the stick twice in the boot menu. Make sure you boot the one that is marked efi/uefi. Then select "Rescue mode" and follow that until you get a chroot into the system. There do a

# grub-install 

without further parameters.

That should fix the issue.

You are thinking in Windows terms.

No, a parallel installation of the amd graphics firmware will not kill you nouveau stuff or interfere in any way. They are no "drivers" in Windows terms. They are just firmware that is required for a reasonable display.

And they are not used at all if the kernel does not detect an AMD graphics during boot.

What you could refer to as driver for the AMD card is already contained in the kernel itself. There are no separate files like for an nvidea card. And there is no split into free and proprietary drivers for AMD. The one thats build in works fine.

firmware-amd-graphics adds firmware files for AMD graphics chips to /lib/firmware/amdgpu so that they are available during boot time. They are only pulled if an AMD graphics card is detected. No need to remove them. They will not hurt.

Otter: refer to https://otter-browser.org/

To get information about your system inxi would be a good choice.

An AMD graphics card requires a suitable kernel and the firmware-amd-graphics package.

From any Linux, use any USB stick that large enough for the iso and can be overwritten, and use cp or dd to the raw device, i.e. /dev/sda. Not to a partition like /dev/sda1.

Well, under the assumption that you have Daedalus installed, you will need to add "non-free-firmware" to your sources.list, do an apt update, and install firmware-amd-graphics, then reboot.