[PATCH] scripts/make_fit: move the dtbs to the start

[Ahmad Fatoum]

On 20.05.25 11:12, Sven Püschel wrote:
> Move the dtbs to the start of the fit image to avoid u-boot overwriting
> the dtb while relocating the kernel image.
> 
> Using a current u-boot master eeb5ff1a468b ("Merge tag
> 'efi-2025-07-rc3-2' of https://source.denx.de/u-boot/custodians/u-boot-efi")
> failed to load a barebox fit image on a Pine64 Rock64 board:
> 
> => bootm $loadaddr#conf-rk3328-rock64.dtb
>    Using 'conf-rk3328-rock64.dtb' configuration
>    Verifying Hash Integrity ... OK
>    Trying 'kernel' kernel subimage
>      Description:  barebox-2025.04.0-00231-g00fd6bfa3088-dirty
>      Type:         Kernel Image (no loading done)
>      Compression:  uncompressed
>      Data Start:   0x00800968
>      Data Size:    737350 Bytes = 720.1 KiB
>    Verifying Hash Integrity ... OK
>    Using 'conf-rk3328-rock64.dtb' configuration
>    Verifying Hash Integrity ... OK
>    Trying 'fdt-1' fdt subimage
>      Description:  rk3328-rock64.dtb
>      Type:         Flat Device Tree
>      Compression:  uncompressed
>      Data Start:   0x008b4a48
>      Data Size:    37415 Bytes = 36.5 KiB
>      Architecture: AArch64
>    Verifying Hash Integrity ... OK
>    Booting using the fdt blob at 0x8b4a48
> Working FDT set to 8b4a48
>    XIP Kernel Image (no loading done) to 800968
> Moving Image from 0x800968 to 0x880000, end=0x934048
> ERROR: image is not a fdt - must RESET the board to recover.
> FDT creation failed!
> resetting ...
> 
> The culprint was the fact that u-boot relocated the barebox image to
> match the alignment requirements from the Linux kernel. But the
> relocation did overwrite the devicetree and therefore failed to boot it.
> 
> To prevent this error from happening, move the dtbs in the generated
> barebox fit image to the start, so u-boot cannot overwrite these when
> moving the kernel image to a higher address.
> 
> Signed-off-by: Sven Püschel <s.pueschel at pengutronix.de>

The point of the FIT image is to make it easier to boot barebox from
existing bootloaders, so a workaround sounds sensible, even if U-Boot
should be ultimately fixed:

Reviewed-by: Ahmad Fatoum <a.fatoum at pengutronix.de>

Sascha, can this go into master? Thanks.

Ahmad

> ---
>  scripts/make_fit.py | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/scripts/make_fit.py b/scripts/make_fit.py
> index 2190da4c00..4253b07e5f 100755
> --- a/scripts/make_fit.py
> +++ b/scripts/make_fit.py
> @@ -267,12 +267,6 @@ def build_fit(args):
>      dtbs_seen = set()
>      fdts = {}
>  
> -    # Handle the kernel
> -    with open(args.kernel, 'rb') as inf:
> -        comp_data = compress_data(inf, 'none')
> -    size += os.path.getsize(args.kernel)
> -    write_kernel(fsw, comp_data, args)
> -
>      for fname in args.dtbs:
>          # Ignore non-DTB (*.dtb) files
>          if os.path.splitext(fname)[1] != '.dtb':
> @@ -297,6 +291,12 @@ def build_fit(args):
>  
>          entries.append([dtbname, model, compat, files_seq])
>  
> +    # Handle the kernel
> +    with open(args.kernel, 'rb') as inf:
> +        comp_data = compress_data(inf, 'none')
> +    size += os.path.getsize(args.kernel)
> +    write_kernel(fsw, comp_data, args)
> +
>      finish_fit(fsw, entries)
>  
>      # Include the kernel itself in the returned file count


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