Hacking Question What is fuse, and burning the fuse?

Cellina

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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.
 

straumli

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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..
 
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Shubshub

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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
 

kkcheong

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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

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
 

AmandaRose

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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
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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kkcheong

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You are wrong. They are tiny and there are thousands. Google efuse.
Why you need thousands of efuse to keep track of firmware revision?

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

AmandaRose

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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.
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.
 

CrAzYLiFe

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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.
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..
 

M-772007

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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..

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,

Ashura66

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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

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
 

bundat

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M-772007

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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

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 ?
 

Ashura66

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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 ?

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
 

M-772007

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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

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 ?
 

Adran_Marit

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Read this

Anti downgrade protection

Firmware Fuse Count HERE

--------------------- MERGED ---------------------------

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 ?
At the moment 5.1.0 is the best to be on, yes
 
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