Installing Arch Linux AArch64 on the NanoPi R2S

There is current no support for the NanoPi R2S in ArchLinuxArm, but it's possible to run it using the generic aarch64 installation.

Prepare sd-card/image

Copy bootloader and uBoot from an armbian image using for the NanoPi R2S using dd (sectors 32 to 32767) everything before the partition, except the partition table).
Create an ext4 partition on /dev/mmcblk0p1 at offset of 32768 sectors (16384 KiB):

Device         Boot Start      End  Sectors  Size Id Type
/dev/mmcblk0p1      32768 15523839 15491072  7.4G 83 Linux

Create the ext4 file system and extract ArchLinuxARM-aarch64-latest.tar.gz to the new partition.
Copy the contents of /boot from the armbian image to /boot on the new patition.
Edit the /boot/armbianEnv.txt to point to the new partition either by UUID or device name (rootdev=/dev/mmcblk0p1)
Boot and follow ArchLinuxArm standard procedures for installation.

Kernel

You can boot with the armbian kernel (currently 5.7.15), or chose to install the arch linux stock aarch64 kernel (linux-aarch64). If you install the stock kernel, a new DTB is needed or USB 3.0 and the secondary ethernet won't work. It works with the rock64 DTB since it has the same Ethernet controller:

ln -sf /boot/dtbs /boot/dtb

Change /boot/armbianEnv.txt to have fdtfile=rockchip/rk3328-rock64.dtb.

Create an uBoot image of the initramfs:

pacman -S uboot-tools
mkimage -A arm64 -T ramdisk -n uInitrd -d /boot/initramfs-linux.img /boot/uInitrd-initramfs-linux.img
ln -sf /boot/uInitrd-initramfs-linux.img /boot/uInitrd

And install a pacman hook to ensure that this is done every time the kernel is upgraded:

mkdir -p /etc/pacman.d/hooks

/etc/pacman.d/hooks/initramfs.hook

[Trigger]
Operation = Install
Operation = Upgrade
Type = Package
Target = linux-aarch64

[Action]
Description = Generate uInitrd
Exec = /usr/bin/mkimage -A arm64 -T ramdisk -n uInitrd -d /boot/initramfs-linux.img /boot/uInitrd-initramfs-linux.img 
When = PostTransaction
Depends = uboot-tools

Serial Gadget

systemctl enable serial-getty@ttyGS0
echo g_serial > /etc/modules-load.d/g_serial.conf

SD-Card layout

Sector	Purpose
0	MSDOS partition table
64	Loader
16384	uBoot
32768	ext4 partition

References

https://wiki.friendlyarm.com/wiki/index.php/NanoPi_R2S

https://wiki.archlinux.org/index.php/NanoPi_NEO_Plus2

larsch/archlinuxarm-on-nanopi-r2s.md