After reading this answer and pointing article: Can somebody explain the boot process of an Android device?

My Samsung S3 have CyanogenMod installed. There is probability while installing custom recovery via Odin to brick your phone.

How does boot process relate to installing custom recovery? Is custom recovery stored in device's BIOS (CPU ASIC??)?

I'm looking for information, about how bricking works (in analogy to PC).
On PC you "brick" computer when your BIOS flash fails rest is handled by bootloader. It could be recovered by dismounting and reflashing bios chip.

So I assume Android devices must have some kind of BIOS also and switch at some point to start booting from media. Is it correct?

On PC if you do not have any OS or it is corrupted you can use different media (floppy, CD) to boot.
Why is it not possible (from what I know) to do such a boot from Memory card?

By my undersanding, as long as BIOS is not corrupted it should be of no problem to boot/reinstall system?

Person installing my recovery told me to ONLY clear cache folders while chaning OS using recovery. So that would mean I cannot touch any core OS functions? Why is that. On normal PC I could just insert CD with new software and install OS from scratch.

The only explanation comes to my head is that BIOS and System is same thing?

  • This is 3 questions in one: How does booting work. What defines bricked. Why can't android boot from external media.
    – jiggunjer
    Feb 12, 2016 at 3:57

1 Answer 1


To put it simply, it is not designed for users to "boot from Memory card" as you put it. It is an embedded device and is designed as such. Android devices are typically not meant for the end user to install software via external media. They are specifically designed for additional software (not new OSes) to be loaded via some network connection. The initial boot parameters are really going to be dependent on the product.

  • They dont make it easier for sure. I'm more interested if there is a way to simplify this process.
    – Gacek
    Feb 17, 2015 at 8:49
  • From my understanding, the Samsung line has had issues in the past where it was possible under certain conditions to hard brick a device. I had an S2 and recall one such issue having to do with how the data was wiped. Either way, it was only one cause/condition. That specific case actually damaged the memory unit which held the bootloader. It was also pretty rare because once people knew the cause it was widely put out until a fix was available. There are surely other conditions but each one would would need to be recovered differently if it can at all. As they say, all this stuff is at your o
    – Goblinlord
    Feb 17, 2015 at 15:20
  • You're probably reffereing to samsung sudden death syndrome.
    – Gacek
    Feb 17, 2015 at 18:02
  • No clue what its called now as I can't really find any information on it anymore. As I recall, it was because the source from Samsung hadn't been released for their builds and there was some issue with the way it was wiping memory. Regardless, what I was trying to say at the end is it is at your own risk. Just like about any post with a ROM states "at your own risk."
    – Goblinlord
    Feb 17, 2015 at 23:27

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .