From: Alison Chaiken alison@she-devel.com
One way for userspace and the bootloader to exchange information about dynamic image selection is via the storage device partition table, as described at
https://source.android.com/devices/tech/ota/ab_updates
The scheme described there relies on setting partitions' "boot" flag. When no partition on a device is bootable since the kernel and U-Boot are stored elsewhere, the name field in the GPT partition table offers another logical place to store information. These patches allow users to easily modify GPT partition names via bootscripts that can select different images based on a boot-failure counter, or when userspace installs a software update.
These patches have been tested on a TI DRA7xx-based SOM with U-Boot 2015.07. The storage device is an eMMC.
Alison Chaiken (3): GPT: add accessor function for disk GUID GPT: read partition table from device into a data structure rename GPT partitions to detect boot failure
cmd/gpt.c | 339 +++++++++++++++++++++++++++++++++++++++++++++++++++++++- disk/part_efi.c | 31 ++++++ include/part.h | 24 ++++ 3 files changed, 392 insertions(+), 2 deletions(-)