Hacking Question Is Downgrade Brick fixable with RCM mode?

[nachuz]

I'm curious if you can fix a Downgrade Brick with RCM mode, a Nand backup and Hekate(Or another app)

 

[OblivionReign]

If a fuse is burnt i do not think so

 

[James310]

You can’t downgrade at all with the fuses in place, there might be ways to do it but it’s too much effort

 

[DocAmes1980]

You could bypass the e fuse check and boot horizon using a payload. I suppose you could also upgrade to a version that matches the number of burnt e fuses.

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

You can’t downgrade at all with the fuses in place, there might be ways to do it but it’s too much effort

Devs say that you could downgrade. It's just that there's no point. The only advantage of lower FW at this point is a being able to enter RCM mode after Horizon has booted. Booting a downgraded Switch requires entering RCM mode from a cold boot (meaning that you still need to ground pin 10).

 

[aos10]

Please read the stickies, it's been known many times, YOU CAN'T DOWNGRADE THE SWITCH.

 

[DocAmes1980]

Please read the stickies, it's been known many times, YOU CAN'T DOWNGRADE THE SWITCH.

You can downgrade, but currently there's not really a point. See above post.

 

[Lacius]

In short, it is possible to downgrade. However, doing so will cause your Switch to be unbootable without Fusée Gelée and CFW, so it's pointless.

 

[aos10]

You can downgrade, but currently there's not really a point. See above post.

That's why i said that, if you manage to restore old NAND, the switch won't boot.
I should mentioned that.

 

[smf]

You can downgrade, but currently there's not really a point. See above post.

You can't downgrade. You can restore an old firmware backup, but it won't boot if the firmware you're on has more fuses burnt than the one you're restoring.

With atmosphere you will be able to boot other firmware versions off an SD card, but that isn't downgrading & you can't currently do it.

 

[SCOTT0852]

Can you downgrade: Yes, but it will brick.
Can you recover from this: Yes, but only if you have a backup from before the downgrade.

 

[INobody]

You can downgrade inside the same burned fuses range.

http://switchbrew.org/index.php?title=Fuses#Anti-downgrade

So 5.1.0 should go down to 5.0.0.

But there is no point doing this, atleast for now


You should be able to fix it with a NAND dump and in future via loading without fuse check and installing a firmware manually (in your burned fuses range).

 

[MHDestination]

Does at least someone here answer the question of the OP?

Is Downgrade Brick fixable with RCM mode?

Yes it is fixable. You need to bypass the fuse check with something like hekate/atmosphere/xs os

If you don't want to do that on every boot, you'll need to update your firmware back
to a version that matches the actually burnt fuses.

 

[Thetoto]

You can't downgrade. You can restore an old firmware backup, but it won't boot if the firmware you're on has more fuses burnt than the one you're restoring.

With atmosphere you will be able to boot other firmware versions off an SD card, but that isn't downgrading & you can't currently do it.

You can do it with hekate.

 

[gamesquest1]

assuming the OP means a brick caused by an attempted downgrade and not just "can I downgrade with RCM", then yeah you could restore a backup from before you attempted the downgrade, in the event you don't have a backup you could probably just use RCM mode to boot the "downgraded" firmware and then manually update to fix the system so its not stuck in a bricked state

 

[SG3xHERO]

assuming the OP means a brick caused by an attempted downgrade and not just "can I downgrade with RCM", then yeah you could restore a backup from before you attempted the downgrade, in the event you don't have a backup you could probably just use RCM mode to boot the "downgraded" firmware and then manually update to fix the system so its not stuck in a bricked state

https://gbatemp.net/threads/how-to-downgrade-5-1-0-to-5-0-2.506315/

I worked out a way on how to downgrade without having to boot RCM everytime

 

[SomeGamer]

https://gbatemp.net/threads/how-to-downgrade-5-1-0-to-5-0-2.506315/

I worked out a way on how to downgrade without having to boot RCM everytime

Of course you don't need to enter RCM if the FW you downgrade to expects the same number of burnt fuses.

 

[SG3xHERO]

Of course you don't need to enter RCM if the FW you downgrade to expects the same number of burnt fuses.

That's what I was saying they said you need to enter RCM everytime to boot it up and it's not possible

 

[gamesquest1]

That's what I was saying they said you need to enter RCM everytime to boot it up and it's not possible

yeah there are a few minor exceptions, but the differences between firmware's that expect the same fuse values is fairly insignificant, assuming people would generally only want to downgrade to take advantage of different exploits , generally if a FW patches an exploit it will trip a fuse afaik everything is now fixed for 5.1.0 (although I haven't had a good look into it)

plus he did specifically say fix a downgrade brick, if you downgrade to a FW with matching effuse values it wouldn't be a brick anyway

 

[DocAmes1980]

You can't downgrade. You can restore an old firmware backup, but it won't boot if the firmware you're on has more fuses burnt than the one you're restoring.

With atmosphere you will be able to boot other firmware versions off an SD card, but that isn't downgrading & you can't currently do it.

You could bypass the efuse check. That's why I say that it is possible. There's no point because the only real advantage of lower firmware is the ability to enter RCM mode from stock firmware. Having to launch a payload from RCM to boot the stock firmware negates its advantage.

So again, yes, you could downgrade. However it is not, at this time, advantageous to do so.