January 20, 2026

Allwinner H5 chip - Build U-boot from source

This is for the Orange Pi PC 2, which I often just call the "H5" as it has the Allwinner H5 chip.

I don't just want to build from source. I want to build an image I can put on an SD card and run. There are several reasons for this. One is that I can add printf statements to help me learn things. The other is that I can get rid of the long delays while U-Boot pokes around for USB devices that I never use.

Previous work

This site has Debian SD card images for a wide variety of ARM boards. I cloned his repo and tried using it as is without success for the RK3328. My notes on that are here: It is relatively easy to study his build scripts and then just do what he did by hand. He very nicely separated the SD card image you need into two parts.
The first is a board dependent ATF (BL31) and U-boot section.
The second is linux itself.

For my purposes I can just ignore the linux section.

I do a diff in his scripts directory: 

cd /Projects/ARM-sources/sd-card-images/scripts
diff build-boot-rk build-boot-sunxi
This indicates only two important differences: 
< rk3328|rk3368|rk3399)
<     build-atf "${CHIP_ID}" "${TUPLE}"
<     export BL31="$PWD/arm-trusted-firmware/build/${CHIP_ID}/debug/bl31/bl31.elf"
<     ;;
> *a64|*h5)
>     build-atf sun50i_a64 "${TUPLE}"
>     export BL31="$PWD/arm-trusted-firmware/build/sun50i_a64/debug/bl31.bin"
>     export SCP=/dev/null
>     ;;
And for the final image: 
< # Copy U-Boot to 64 sectors from start
< dd if=u-boot/u-boot-rockchip.bin of=tmp.img seek=64 conv=notrunc
---
> # Copy U-Boot to 8192 bytes from start
> dd if=u-boot/u-boot-sunxi-with-spl.bin of=tmp.img bs=1K seek=8 conv=notrunc

Build ATF

cd /Projects/ARM-sources/
cd arm-trusted-firmware
make clean
make PLAT="sun50i_a64" DEBUG=1 bl31
I get this: 
/usr/bin/aarch64-linux-gnu-ld: BL31 image has exceeded its limit.
/usr/bin/aarch64-linux-gnu-ld: region `RAM' overflowed by 216 bytes
I try again without the DEBUG option: 
make clean
make PLAT="sun50i_a64" bl31
This works fine and ends like so: 
  LD      /u2/Projects/ARM-sources/arm-trusted-firmware/build/sun50i_a64/release/bl31/bl31.elf
  BIN     /u2/Projects/ARM-sources/arm-trusted-firmware/build/sun50i_a64/release/bl31.bin
  OD      /u2/Projects/ARM-sources/arm-trusted-firmware/build/sun50i_a64/release/bl31/bl31.dump
Built /u2/Projects/ARM-sources/arm-trusted-firmware/build/sun50i_a64/release/bl31.bin successfully

Build U-boot

cd /Projects/ARM-sources/
cd u-boot
export BL31="/Projects/ARM-sources/arm-trusted-firmware/build/sun50i_a64/release/bl31/bl31.elf"
export CROSS_COMPILE=aarch64-linux-gnu-
export LOCALVERSION="trebisky"
export SCP=/dev/null
make distclean
make clean
make orangepi_pc2_defconfig
make
On my machine, the build takes 3 minutes. It ends as follows: 
  OBJCOPY spl/u-boot-spl-nodtb.bin
  COPY    spl/u-boot-spl.bin
  SYM     spl/u-boot-spl.sym
  MKIMAGE spl/sunxi-spl.bin
  MKIMAGE u-boot.img
  COPY    u-boot.dtb
  MKIMAGE u-boot-dtb.img
  BINMAN  .binman_stamp
Image 'u-boot-sunxi-with-spl' is missing optional external blobs but is still functional: scp

/binman/u-boot-sunxi-with-spl/fit/images/scp/scp (scp.bin):
   SCP firmware is required for system suspend, but is otherwise optional.
   Please read the section on SCP firmware in board/sunxi/README.sunxi64

  OFCHK   .config
Note the line above that exports SCP as /dev/null -- this was present in the build scripts, but I did not include it in the build I just did. Next time.

generate the SD card image

This gets done in the directory above the U-boot directory. 
cd /Projects/ARM-sources
# Copy U-Boot to 8192 bytes from start
dd if=u-boot/u-boot-sunxi-with-spl.bin of=h5.img bs=1K seek=8 conv=notrunc
ls -l h5.img
-rw-r--r-- 1 tom tom 1153629 Jan 20 21:36 h5.img
So the image is just a bit bigger than 1M. 
su
dd if=h5.img of=/dev/sdf
sync
I plug the card in, cycle power, and get this: 
U-Boot SPL 2026.01-rc3trebisky-00026-g31bf4a1c3087 (Jan 20 2026 - 21:28:09 -0700)
DRAM: 1024 MiB
Trying to boot from MMC1
alloc space exhausted ptr 10fe00 limit 100000
Could not get FIT buffer of 1113088 bytes
	check CONFIG_SPL_SYS_MALLOC_F_LEN
The messages from my ancient (but working) SD card are: 
U-Boot SPL 2020.04-armbian (Jun 03 2020 - 07:47:47 +0200)
DRAM: 1024 MiB
Trying to boot from MMC1
NOTICE:  BL31: v2.3(debug):ec29ce6-dirty
NOTICE:  BL31: Built : 07:47:38, Jun  3 2020
I see a report where the malloc len had been reduced from 0x10000 to 0x8000 and this had caused bugs. Looking at my .config file I see: 
CONFIG_SYS_MALLOC_F_LEN=0x2000
CONFIG_SPL_SYS_MALLOC_F_LEN=0x2000
So, I add these 2 lines to configs/orangepi_pc2_defconfig 
CONFIG_SYS_MALLOC_F_LEN=0x10000
CONFIG_SPL_SYS_MALLOC_F_LEN=0x10000
Then I repeat the build: 
cd /Projects/ARM-sources/
cd u-boot
export BL31="/Projects/ARM-sources/arm-trusted-firmware/build/sun50i_a64/release/bl31/bl31.elf"
export CROSS_COMPILE=aarch64-linux-gnu-
export LOCALVERSION="trebisky"
export SCP=/dev/null
make distclean
make clean
make orangepi_pc2_defconfig
make
cd ..
dd if=u-boot/u-boot-sunxi-with-spl.bin of=h5.img bs=1K seek=8 conv=notrunc
su
dd if=h5.img of=/dev/sdf
sync
exit
Now I get nothing at all on the console when I try to boot the card! Maybe I was too extravagant.
I try this and rebuild: 
CONFIG_SYS_MALLOC_F_LEN=0x4000
CONFIG_SPL_SYS_MALLOC_F_LEN=0x4000
Now I get this on the console: 
U-Boot SPL 2026.01-rc3trebisky-00026-g31bf4a1c3087-dirty (Jan 20 2026 - 22:19:01 -0700)
DRAM: 1024 MiB
Trying to boot from MMC1
alloc space exhausted ptr 10fe00 limit 100000
Could not get FIT buffer of 1113088 bytes
	check CONFIG_SPL_SYS_MALLOC_F_LEN

Have any comments? Questions? Drop me a line!

Tom's electronics pages / tom@mmto.org