[U-Boot] [PATCH v3 3/7] common: Implement A/B metadata

[Eugeniu Rosca]

jFYI/FWIW, AOSP U-Boot [1] seems to currently import the bootloader
message header [2] at least twice:
 - as include/android_bl_msg.h via
   https://android.googlesource.com/platform/external/u-boot/+/86a4b492b5db%5E!/
 - as include/android_bootloader_message.h via
   https://android.googlesource.com/platform/external/u-boot/+/c7f85c5f75f9%5E!/

[1] https://android.googlesource.com/platform/external/u-boot
[2] bootable/recovery/bootloader_message/include/bootloader_message/bootloader_message.h

> Best regards,
> Eugeniu.