Assorted resources about the Allwinner Nezha D1 RISC-V development board

Some useful links

• Allwinner documentation
• sunxi wiki: Allwinner Nezha page
• sunxi wiki: D1 page
• RVBoards D1 demos
• RVBoards D1 documentation (source)
• riscv.org devboard-community mailing list
• D1 40-pin header pin-out label
• Fedora RISC-V wiki pages: D1-specific information, generic installation guide
• Tiny FEL tools for Allwinner SoC
• D1 buildroot for Docker containers
• Source code of this page

Hardware

Power supply

Robert Lipe notes that Apple hardware and Nezha D1 do not work together using a USB-C to USB-C cable. It should be possible to work around the problem using the USB-A to USB-C cable(s) supplied with the board.

SPI NAND layout

Kernel 5.4.61 (as reported by Gabe R):

mtd0: 00100000 00040000 "boot0"
mtd1: 00400000 00040000 "uboot"
mtd2: 00100000 00040000 "secure_storage"
mtd3: 0fa00000 00040000 "sys"

Kernel 5.16.0-rc2:

# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 10000000 00020000 "spi0.0"

Some files (may be mirrored locally, or not)

Notes

2

Pristine disk images as published by PerfXLab & RVBoards.

3

Pristine disk images from MEGA as published by Sipeed.

4

This disk image requires a 2 TiB device, of which it allocates only the first 29.5 GiB with GPT, of which it fills only the first 4.03 GiB with data. Because of these discrepancies D1 cannot boot from this disk image.

5

By Gary E. Miller.

6

As published on Fedora RISC-V wiki and openkoji service of Institute of Software, Chinese Academy of Sciences.

7

The Linux kernel in this disk image does not auto-detect the RAM size, but uses a hard-coded size from a DeviceTree file. Each boot menu item has its own DeviceTree file, and the default boot menu item (1) stands for 2 GB:

Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide-20210912.n.0 Boot Options.
1:      Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide (5.4.61+ 2G)
2:      Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide (5.4.61+ 1G)
3:      Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide (5.4.61+ 512M)
4:      Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide (5.4.61+ 128M)
Enter choice: 1:        Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide (5.4.61+ 2G)
[...]
Retrieving file: /aw_nezha_d1_2G.dtb

If you try to use more RAM than the D1 board actually has, it will sooner or later crash. The following commands can be used to change the default to 1 GB:

# For the 2021-09-12 revision:
echo 'default Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide (5.4.61+ 1G)' >>/boot/extlinux/extlinux.conf

# For the 2021-11-30 revision:
echo 'default Fedora-riscv64-d1-developer-xfce-with-esp-Rawhide (5.4.16.riscv64.fc33.riscv64 1G)' >>/boot/extlinux/extlinux.conf

8

To boot the latest kernel, this image requires booting through GRUB. This can be done manually during the boot sequence as follows:

[...]
Importing environment from mmc0 ...
Autoboot in 2 seconds  <---------------------------------- press "v"
[Nezha]#
[Nezha]# run boot_grub
4681728 bytes read in 808 ms (5.5 MiB/s)
Scanning disk mmc@4020000.blk...
Scanning disk mmc@4021000.blk...
Disk mmc@4021000.blk not ready
Found 4 disks
No EFI system partition
Booting /\EFI\fedora\grubriscv64.efi
Welcome to GRUB!
[...]

The following command can be used after booting to have U-Boot load GRUB by default:

echo 'bootcmd=run boot_grub' >>/boot/boot/uEnv.txt

9

When booting the latest kernel from this image, it will use the RAM size provided by U-Boot, not the RAM size in DeviceTree files. However, U-Boot in this image has the RAM size hard-coded to 2GB, so to work with the latest kernel on D1-1GB this image requires to replace the bootloader with a custom version (provided by Fu Wei):

dd if=fedora-2021-11-30_D1-1GB_bootloader.bin bs=512 seek=32800 of=/dev/mmcblk0