I'm really really sorry if this is a useless thread but I don't know who else to talk to about this if this is even possible. Is it possible that you can modify a nand dump and downgrade it then restore the nand just like how you are able to downgrade the Nintendo Wii (Just an example).
In most cases, no, because the switch has something called fuses. The fuses tell the switch what OS version it should have, and if it has something different the switch won't turn on.
EDIT: If we get CFW that ignores what the fuses say, then it's possible
Efuses would prevent you from booting it directly, but you could probably boot into it using the RCM vulnerability (but that would also mean you'd need to do that everytime you boot the switch)
The fuses are already burnt and are separate from the nand. If you restore a nand backup, it won't restore fuses to the necessary state.
You could theoretically use the bootrom hack to run any version of the system software you'd like but the best way to do so would not be by modifying the actual nand . your best bet would be an "emunand" with all the securities patched out by the loader. Though for the life of me I can not imagine it would be all that helpful to downgrade.
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Ive also wondered this myself. Lets say in theory you could dg to 1.0 and install a custom patch to bypass fuse check. Then lets say a software only full cold boot comes along (fingers crossed since I'm still on 1.0) it may in theory let you then boot into emunand.
Just a theory but it would be nice
Just a theory but it would be nice
If you have a patch to bypass the fuse check, then you already have a patch to cold boot into emunand.
There is no way to downgrade an updated switch. If the console is using an exploit to load old firmware, bypassing efuse checks, it is not a downgrade. Without the exploit it would be a brick.
eFuses work just like any other fuse. If it's blown, it is blown, there is no software to reset it as it is an electronic short, not a bit or register.
That said, there are a few use case scenarios, but those are few and becoming less.
eFuses work just like any other fuse. If it's blown, it is blown, there is no software to reset it as it is an electronic short, not a bit or register.
That said, there are a few use case scenarios, but those are few and becoming less.
No you can't.
Modifying the NAND would cause it to fail signature checks.
You can't resign it because we don't have the private keys (which are different from the public keys we currently have)
You could patch signature checks, but at that point you have access to just running cfw anyway, meaning there would be no benefit to using it.
Modifying the NAND would cause it to fail signature checks.
You can't resign it because we don't have the private keys (which are different from the public keys we currently have)
You could patch signature checks, but at that point you have access to just running cfw anyway, meaning there would be no benefit to using it.
Sure, you can ignore the fuses with CFW, but if you already have CFW then there's no point in downgrading...
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It happened on Xbox 360 so I'm sure it could happen here.
Give the Devs time to research the boot process.
Give the Devs time to research the boot process.
What would downgrading get you?
There is no point in downgrading. A fully working Emunand or CFW with signature patches is the best case scenario.
As has previously been stated the FW checks that the number of burnt efuses match the hardcoded figure in the firmware. If not a kernel panic and ensues and your switch is effectively dead.
Efuses are impossible to revert back to their unburnt state once tripped. There would be no benefit from running a downgraded OS anyway as you lose the ability to play game that require a newer FW.
Once Scires finishes Atmosphere we will see what benefits we get and where others can expand on the work.
There is no point in downgrading. A fully working Emunand or CFW with signature patches is the best case scenario.
As has previously been stated the FW checks that the number of burnt efuses match the hardcoded figure in the firmware. If not a kernel panic and ensues and your switch is effectively dead.
Efuses are impossible to revert back to their unburnt state once tripped. There would be no benefit from running a downgraded OS anyway as you lose the ability to play game that require a newer FW.
Once Scires finishes Atmosphere we will see what benefits we get and where others can expand on the work.
Started from a modchip, or having to be tethered to another powered device on every boot.
Then getting banned from N being able to detect the modchip based on voltage fluctuations. (The last part is not that likely - but still.. )Of course you could run it in CFW if they are getting updated regularly.
Just not online, for long. Probably. (Depending on a couple of unknowns).
Last edited by notimp,
I've seen this question pop up a few times and I also had the thought myself. However it won't work.
The Switch has e-fuses, which act as a permanent counter in the processor.
The Switch bootloader (The 2cd piece of code to run after the bootrom) checks the values of the e-fuses (http://switchbrew.org/index.php?title=Fuses#Anti-downgrade)
If the value of the firmware is too low compared to the e-fuses because you've tried to downgrade then the bootloader will not continue any further.
There is a way to downgrade but it's not very useful, see here.
The Switch has e-fuses, which act as a permanent counter in the processor.
The Switch bootloader (The 2cd piece of code to run after the bootrom) checks the values of the e-fuses (http://switchbrew.org/index.php?title=Fuses#Anti-downgrade)
If the value of the firmware is too low compared to the e-fuses because you've tried to downgrade then the bootloader will not continue any further.
There is a way to downgrade but it's not very useful, see here.
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