/misc partition layout
September 23, 2021 · View on GitHub
| - | - | - | Size | description | Offset |
|---|---|---|---|---|---|
| Legacy | bootloader_message | (2K) | --> 0 | ||
| command | 32 | updated by linux/bootloader | |||
| status | 32 | deprecated | |||
| recovery | 768 | talking channel between normal/recovery modes | |||
| stage | 32 | format "#/#", eg, "1/3" | |||
| reserved | 1184 | ||||
| - | - | - | - | - | |
| Vendor Area | vendor bootloader msg | N/A | 2K | Vendor Area | -->2KB |
| vendor bootloader msg | N/A | 12K | pure Vendor area | -->4KB | |
| - | - | - | - | - | |
| Wipe | wipe_package info | 16K | offset 16KB, Used by uncrypt and recovery to store wipe_package for A/B devices | -->16KB | |
| - | - | - | - | - | |
| System | system_space -> 1 misc_virtual_ab_message | (64) | -->32KB | ||
| version | 1 | ||||
| magic | 4 | ||||
| merge_status | 1 | ||||
| source_slot | 1 | ||||
| reserved | 57 | ||||
vendor area implementation example from Google:
bootctrl.default.so (link libboot_control.a)貌似没人用
使用legacy_boot_control.cpp, 把libboot_control.a的实现的类android::bootable::BootControl包装进去
android.hardware.boot@1.1-impl
使用BootControl.cpp
android::hardware::boot::V1_1::implementation::BootControl
直接使用"android::bootable::BootControl"的实现
libboot_control.a
code location:
hardware/interfaces/boot/1.1/default/boot_control
| - | - | - | Offset | Size | description |
|---|---|---|---|---|---|
| Vendor Area | bootloader_message_ab | 2K | (2K) | Vendor Area | |
| slot_suffix | 32 | ||||
| update_channel | 128 | ||||
| reserved | 1888 |
32 BYTES "slot_suffix" part details:
| - | - | - | Offset | Size | description |
|---|---|---|---|---|---|
| bootloader_control | (32) | ||||
| slot_suffix | 4 | ||||
| magic | 4 | ||||
| version | 1 | ||||
| nb_slot | 3bits | number slots | |||
| recovery_tries_remaining | 3bits | ||||
| merge_status | 3bits | ||||
| reserved0 | 1 | ||||
| slot_info | 8 | slot_metadata * 4 | |||
| reverved1 | 8 | ||||
| crc32_le | 4 | ||||
| slot_metadata | (2) | ||||
| priority | 4bits | ||||
| tries_remaining | 3bits | ||||
| successful_boot | 1bit | ||||
| verity_corrupted | 1bit | ||||
| reserved | 7bits | ||||