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I'm looking through my device and I noticed within /dev/block/platform/msm_sdcc.1/by-name that there is boot and aboot partitions. What is the difference between them? Mainly what is aboot?

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The Application Bootloader ABOOT boots the Android kernel/Recovery kernel.

It is the mechanism to download images onto the device from a host machine (like Windows/Linux PC).

On Samsung devices it runs the ODIN protocol on the device.

The Primary Bootloader boot part is a computer program that loads the main operating system or runtime environment for the computer after completion of the self-tests.

The PBL acts as a communication engine to download the Secondary Boot Loader (SBL) into the internal RAM and then activates it.

The SBL adds functions for erase and programming of flash memory and EEPROM; it also handles the actual download of new or updated software. This allows a minimum ROM utilization by the PBL

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  • And what about the SBOOT
    – Jenabictak
    Commented Apr 22, 2018 at 7:13
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    Boot chain goes like this: Power ON --> BootRom/PBL --> SBL --> aboot --> boot | recovery. Boot is kernel (+ ramdisk optionally), not PBL. PBL is stored on SoC, all others are on flash storage partitions. Commented Nov 10, 2019 at 17:47
  • @IrfanLatif I wonder if an Android device exists where SBL can be loaded also from an SD card. There would be no danger of bricking any more, and no more hard-or-impossible rootable devices.
    – peterh
    Commented Jan 26, 2021 at 13:32
  • @peterh-ReinstateMonica my first question on Android SE (which was marked off-topic) was about breaking the bootloader boot chain in order to boot from SD card. The problem is that everything that loads before Linux kernel is signed with OEM's private keys (check Android Verified Boot), including SBL (or equivalents). And secondly the locations (offsets or filesystem paths) from where to load the next components are hard-coded (except on some develeopment boards/SoCs which provide a switch to change the location). In most cases it's not possible to cope with the both limitations. Commented Jan 26, 2021 at 14:21
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