Question What is fuse, and burning the fuse?

Discussion in 'Switch - Exploits, Custom Firmwares & Soft Mods' started by Cellina, Sep 11, 2018.

  1. Cellina
    OP

    Cellina Member

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    Feb 6, 2017
    I'm kinda newbie to the Switch Hacking, and while I was looking to lots of switch hacking threads, I found out that lots of threads do contain the word fuse and the term fuse burning.
    I was trying to figure the meaning out, but I still don't get it.
     
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  2. straumli

    straumli Member

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    May 17, 2018
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    I believe as security measure nowadays chips have HW based 'fuses' that can be physically burned away. This burning of fuses is done iterative after every FW upgrade. On a software level each firmware checks if the max amount of fuses are spend/burned or not. This prevents installing OLDER firmware version that might contain software exploits. default FW can be installed if 0 fuses have been burned (hardcoded in FW). Firmware 2.0 demands that no more than 1 fuses are burned. etc..
     
  3. Shubshub

    Shubshub The Shubinator

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    Oct 16, 2009
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    The dark part of your house
    The fuse is a physical component on the board there are thousands of them
    They are used as a hardware method to prevent downgrading. Firmware requires a specific number of fuses to be burnt for it to be bootable
    So if there are more fuses burnt then the firmware wont boot

    Burning a fuse is literal that fuse has been burnt out made non-functional so there are less fuses left
    When firmware 6.0 comes out another fuse will probably be burnt preventing anybody from going back to 5.1.0
     
  4. kkcheong

    kkcheong GBAtemp Regular

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    May 15, 2018
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    There is only few fuses and it's in the cpu and not board. Fuses is huge and so it cannot be thousands

     
  5. CrAzYLiFe

    CrAzYLiFe Advanced Member

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    Aug 4, 2007
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    You are wrong. They are tiny and there are thousands. Google efuse.
     
  6. AmandaRose

    AmandaRose Do what I do. Hold tight and pretend it’s a plan

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    Aug 19, 2015
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    The xbox 360 had 786 efuses nobody knows for sure how many the switch has but its rumoured to be over 7000 so your comment is totally wrong.
     
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  7. Milenko

    Milenko GBAtemp Advanced Maniac

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    Oct 16, 2017
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    Burning = bad
     
  8. kkcheong

    kkcheong GBAtemp Regular

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    Why you need thousands of efuse to keep track of firmware revision?

    Big CPU such as Xbox 360 don't even have thousand. So my comment is totally right.
     
  9. AmandaRose

    AmandaRose Do what I do. Hold tight and pretend it’s a plan

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    You said the switch has only a few fuses yet it is a know fact it has more than the xbox so that is hardly a few.
     
  10. CrAzYLiFe

    CrAzYLiFe Advanced Member

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    Aug 4, 2007
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    The 360 has 768 fuses to blow, alot more then a "few" being 1-4.. your comment is still totally wrong.

    I dont know why they would need thousands, they could be used for anything not just firmware, having more then will be ever needed would be better then running out of fuses to blow for nintendo.

    Im not sure on the exact number of fuses the switch has, but being a newer cpu then the 360 one would assume the number to be over 1000. Alot more then a few anyway..
     
  11. M-772007

    M-772007 Newbie

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    Sep 12, 2018
    Latvia
    It seems that you understand about modifies devices
    I am a newbie so I thought asking here is better than starting new thread, I hope you can help me plz
    So, my Nin switch was hacked by my friend using sx pro , i'll get it after a week
    I think it will be on 1.4v
    And my OFW switch is 3.0.0
    I am thinking of updating the sx os to the latest version 1.9
    ..
    After that can I update my OFW to the latest safely ? 5.1.0 I think
    Or it will burn the fuses ?
    From what I understood from you that "burning fuses only occur after downgrade to lower version not from upgrading to latest"
    + does sx os 1.9 will prevent burning fuses or not? (Upgrade and downgrade)

    *sorry if my English is weak
     
    Last edited by M-772007, Sep 12, 2018
  12. Ashura66

    Ashura66 GBAtemp Advanced Maniac

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    Feb 1, 2016
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    No no no no no you got it all wrong. UPGRADING to a HIGHER firmware is what burns fuses. Burning the fuses then prevents you from DOWNGRADING to a lower firmware
     
  13. bundat

    bundat ¿

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    Jul 25, 2018
    Antarctica
    An efuse is around 100 nm.
    A bacterial cell is 1 micrometer (1000 nm).
    Also:
    So no, "huge" is not "totally right".
    More like COMPLETELY WRONG.
     
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  14. M-772007

    M-772007 Newbie

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    Sep 12, 2018
    Latvia
    Oh so when I upgrade my FW the fuses will burn
    .. Then it doesn't really matters for those who will never downgrade their FW right ?

    Can I ask why people downgrading their FW? From what I heard everything is 100% compatible with the last FW version + a lot of games will only work in high FW version!
    Why even thinking of a downgrade ?
     
  15. Ashura66

    Ashura66 GBAtemp Advanced Maniac

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    Feb 1, 2016
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    Well there is the POSSIBILITY that in the future, lower firmwares will have different option to boot into CFW without having to use a dongle or a USB cable to connect to the pc but it's highly unlikely that those options will come to higher firmwares. It's also there so that, int he eventuality that a higher firmware version breaks something like homebrews or backup running or something like that, you can downgrade until the problem is fixed
     
  16. M-772007

    M-772007 Newbie

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    Sep 12, 2018
    Latvia
    Thanks this helps a lot
    But I think i will update to 5.1 and stick to it , and never update again until i really had to , 5.1 its kinda a safe zone that compatible with all games and CFW
    What do you think ?
     
  17. Adran_Marit

    Adran_Marit Walküre's Hacker

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    Oct 3, 2015
    Australia
    42*South
    Read this

    Anti downgrade protection

    Firmware Fuse Count HERE

    — Posts automatically merged - Please don't double post! —

    At the moment 5.1.0 is the best to be on, yes
     
  18. kkcheong

    kkcheong GBAtemp Regular

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    May 15, 2018
    Malaysia
    Well, still huge for silicon real estate. Agree?
     
  19. bundat

    bundat ¿

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    Jul 25, 2018
    Antarctica
    OR you could just admit you were totally wrong in saying that the efuses are "huge" and "few".
     
  20. M-772007

    M-772007 Newbie

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    Sep 12, 2018
    Latvia
    Thanks! you guys are awesome
     
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