I'm back. I have UART converter. My plan is to test the peripherals - I2C at this moment. Since the armbian-config does not allow to configure device tree overlays I figured it out how to do it manually. I edit the file: `/boot/extlinux/extlinux.conf` to add additional line: fdtoverlays /boot/dtb/spacemit/overlay/k1-i2c4.dtbo It seems that U-Boot is ok with this: [ 9.909] Retrieving file: /boot/dtb/spacemit/k1-orangepi-rv2.dtb [ 9.935] Retrieving file: /boot/dtb/spacemit/overlay/k1-i2c4.dtbo [ 9.964] Uncompressing Kernel Image [ 10.316] Moving Image from 0x10000000 to 0x200000, end=27c4000 [ 10.337] ## Loading init Ramdisk from Legacy Image at 21000000 ... [ 10.340] Image Name: uInitrd [ 10.343] Image Type: RISC-V Linux RAMDisk Image (gzip compressed) [ 10.349] Data Size: 21020117 Bytes = 20 MiB [ 10.354] Load Address: 00000000 [ 10.357] Entry Point: 00000000 Verifying Checksum ... OK [ 10.458] ## Flattened Device Tree blob at 31000000 [ 10.459] Booting using the fdt blob at 0x31000000 [ 10.565] Loading Ramdisk to 7c974000, end 7dd7fdd5 ... OK [ 10.584] Loading Device Tree to 000000007c952000, end 000000007c973fff ... OK Starting kernel ... And I'm able to see additional `i2c-4` device: $ sudo i2cdetect -l i2c-0 i2c spacemit-i2c-adapter I2C adapter i2c-1 i2c spacemit-i2c-adapter I2C adapter i2c-2 i2c spacemit-i2c-adapter I2C adapter i2c-4 i2c spacemit-i2c-adapter I2C adapter i2c-8 i2c spacemit-i2c-adapter I2C adapter I'll test some sensors now...

Armbian is I think the easiest way to get Linux running on many many SBC's, but it is already pre-installed. So just 1 OS 1 boot method. If you want more , it is all DIY. Same as if you buy a a Windows laptop and want Linux on it essentially. Or just a DIY build PC where you put Linux on. You will need to understand disks, partitions, BIOS settings etc. But as you say Armbian is a good start as it is Linux so all can be done. An Armbian image for the RK35xx based SBC also contains the proper U-Boot, it is just that that U-Boot uses boot.scr as primary boot method. So if you remove or rename that file, it tries other methods, like extlinux and also as you need, EFI. But it needs to find a partition of type 0xEF00 and just FAT formatted with /EFI/boot/bootaa64.efi on it (or maybe Ext4 also works, at least it does not for computers with UEFI BIOS, those can only read FAT). What you can do to test is to move/delete/rename boot.scr in the rootfs of the Armbian install on the SD-card and then have/put a Armbian UEFI for Aarch64 on NVME/SSD/USB-stick. Or just hide/delete all partitions on the SD-card, then it is essentially only a storage place for U-Boot, same as EEPROM/SPI-NOR-flash on SBC's that have such a chip. Of course you can also go straight to Guix installing yourself, from iso9660 tha tyou put on CD-ROM or USB-stick. But advice is to have a serial console cable connected as U-Boot normally does not initialize HDMI, so don't come here and report 'black screen it does not work'.

@bedna Yeah, that's exactly what I was asking. I found out how to install armbian on the NVMe, which is simply to run armbian install and it does it automatically for you. I don't see why that would be impossible if one can boot Armbian with Armbian. Is the '/boot' section that much geared to a distro? I thought that was just the linux kernel part. I also get the feeling that I would probably not need Armbian at all, but u-boot installed on the SD card, but that installing Armbian was at least a good start to see if everything was working and what the guix system ARM iso file is an iso9660 filesystem meant for a USB device, meaning that that I would need a pure u-boot installed on the SD card to first boot the USB device run the guix system installer and then have u-boot boot the NVMe device. I say 'pure u-boot' because I sometimes see these u-boot.img files floating around on the web and just assume these might be the thing that I'm looking for. I have no idea really.

From what I've seen, that particular tool is not as well maintained as some others. If it's a major uboot failure, it won't boot. If it's working, I think that's your answer.

It may be possible. But due to limited resources, forum support is limited to using Armbian as-is. Everything else goes in Off Topic. If you're truly interested, you could attempt to take the Armbian bootloader, kernel, and device tree, and drop that into a Guix install. But at that point, you are very much on your own.