Ubuntu 20.04 supports six major architectures and several variations of each architecture known as “flavors”. One other architecture (IBM/Motorola PowerPC) has an unofficial port.

ARM systems are much more heterogeneous than those based on the i386/amd64-based PC architecture, so the support situation can be much more complicated.

The ARM architecture is used mainly in so-called “system-on-chip” (SoC) designs. These SoCs are designed by many different companies, often with vastly varying hardware components even for the very basic functionality required to bring the system up. Older versions of the ARM architecture have seen massive differences from one SoC to the next, but ARMv8 (arm64) is much more standardised and so is easier for the Linux kernel and other software to support.

Server versions of ARMv8 hardware are typically configured using the Unified Extensible Firmware Interface (UEFI) and Advanced Configuration and Power Interface (ACPI) standards. These two provide common, device-independent ways to boot and configure computer hardware. They are also common in the x86 PC world.

Ubuntu provides generic arm64 kernel images for various supported platforms listed in Ubuntu Wiki. You can check that page for platform-specific installation notes.

When using debian-installer on non-UEFI systems, you may have to manually make the system bootable at the end of the installation, e.g. by running the required commands in a shell started from within debian-installer. flash-kernel knows how to set up an X-Gene system booting with U-Boot.

Multiprocessor support — also called “symmetric multiprocessing” or SMP — is available for this architecture. Having multiple processors in a computer was originally only an issue for high-end server systems but has become common in recent years nearly everywhere with the introduction of so called “multi-core” processors. These contain two or more processor units, called “cores”, in one physical chip.

The standard Ubuntu 20.04 kernel image has been compiled with SMP support. It is also usable on non-SMP systems without problems.

Ubuntu's support for graphical interfaces is determined by the underlying support found in X.Org's X11 system, and the kernel. Basic framebuffer graphics is provided by the kernel, whilst desktop environments use X11. Whether advanced graphics card features such as 3D-hardware acceleration or hardware-accelerated video are available, depends on the actual graphics hardware used in the system and in some cases on the installation of additional “firmware” images (see Section 2.2, “Devices Requiring Firmware”).

Nearly all ARM machines have the graphics hardware built-in, rather than being on a plug-in card. Some machines do have expansion slots which will take graphics cards, but that is a rarity. Hardware designed to be headless with no graphics at all is quite common. Whilst basic framebuffer video provided by the kernel should work on all devices that have graphics, fast 3D graphics invariably needs binary drivers to work. The situation is changing quickly but at the time of the focal release free drivers for nouveau (Nvidia Tegra K1 SoC) and freedreno (Qualcomm Snapdragon SoCs) are available in the release. Other hardware needs non-free drivers from 3rd parties.

Details on supported graphics hardware and pointing devices can be found at http://xorg.freedesktop.org/. Ubuntu 20.04 ships with X.Org version 7.7.

Almost any network interface card (NIC) supported by the Linux kernel should also be supported by the installation system; drivers should normally be loaded automatically.

On 64-bit ARM, most built-in Ethernet devices are supported and modules for additional PCI and USB devices are provided.

Linux supports a large variety of hardware devices such as mice, printers, scanners, PCMCIA/CardBus/ExpressCard and USB devices. However, most of these devices are not required while installing the system.