Folders and files
NixOS on the Anbernic RG552 (RK3399). Builds U-Boot, ARM Trusted Firmware, and a custom Linux 6.18.20 kernel with ROCKNIX hardware patches — all from source in Nix — and produces a flashable SD card image.
Heavily leaned on the ROCKNIX project for devicetrees, patches, and kernel drivers + pine project for docs
- Build the SD image: nix build .#packages.aarch64-linux.sdImage
- Flash: sudo dd if=result/sd-image/*.img of=/dev/sdX bs=4M status=progress conv=fsync
- Build just the kernel: nix build '.#kernel'
- Build just U-Boot: nix build '.#uboot'
- Serial console (for debugging): UART2 on GPIO pins 6 (GND), 8 (TX), 10 (RX) — screen /dev/ttyUSB0 1500000
- both uboot and the kernel log at this baud. you can find these pins right next to the fan (they are labeled)
The RK3399 ROM loads a bootloader from a fixed offset, then U-Boot reads the firmware partition to boot Linux.
| Region | Sector | Offset | Contents |
|---|---|---|---|
| MBR/GPT | 0–63 | 0x0 | Partition table |
| idbloader (TPL+SPL) | 64+ | 32 KB | DRAM init + Secondary Program Loader |
| u-boot.itb | 16384+ | 8 MB | U-Boot + ATF BL31 (FIT image) |
| Firmware (FAT32) | 32768+ | 16 MB | Kernel Image, initrd, device tree, boot.scr |
| Root (ext4) | after firmware | — | NixOS root filesystem |