TITLE: Mainline U-Boot 2022.04 on RockPro64 - works from SD card
DATE: 2022-06-05
TAGS: rockpro64 sbc u-boot aarch64 software
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Had to downgrade gcc to version 11 on Arch ARM (otherwise ATF won't build),
then (using git repos):

  arm-trusted-firmware $ git checkout v2.7.0
  arm-trusted-firmware $ find . -name '*.bin' -exec rm -vf '{}' \;
  arm-trusted-firmware $ make PLAT=rk3399 bl31
  arm-trusted-firmware $ cd ../u-boot
  u-boot $ git checkout v2022.04
  u-boot $ make mrproper && make rockpro64-rk3399_defconfig
  u-boot $ make BL31=../arm-trusted-firmware/build/rk3399/release/bl31/bl31.elf

Create a GPT partition on SD card to hold boot files:

  /boot1GiBSD/
  ├── boot_arch
  │   ├── dtbs/
  │   ├── Image
  │   └── initramfs-linux.img
  └─── extlinux
      └── extlinux.conf

Write U-boot image to the same SD card (it will not break GPT) - directions in
`doc/README.rockchip` in U-boot source tree, "Booting from an SD card on
RK3399", Option 3. Works fine.

SPI flash doesn't work though, `sf probe` complains:

  unrecognized JEDEC id bytes: ff, ff, ff