Purple screens?
Black screens?
Just Switch logo and then nothing?
These are just a few examples of what you will face unless you fully understand what downgrading your switch means.
You cannot just willy nilly downgrade your switch to any firmware version that you find online and expect it to cold boot to official firmware without issues.
Your fuse count MUST match the firmware version that you are downgrading to and the boot0 and boot1 files that you use are console specific and firmware specific. If you just flash a firmware to your switch that you found online and it doesn't contain these console specific files and the fuse counts don't match then you are going to have issues.
Every time you cold boot your Switch to official firmware (not RCM and custom payload) the console checks to see if your fuse count matches the firmware that is on the sysnand. If you're booting a higher firmware than your fuse count then the Switch will just burn the fuses to match the higher firmware. If your firmware is lower than what your fuse count indicates then the switch won't boot at all. You'll only be able to boot at that point with RCM and a custom bootloader that ignores the fuse count.
If you previously updated your Switch using Choidejour and turned on AutoRCM then your fuse count should stay low enough for you to restore your nand backup that you made previous to upgrading the firmware on the sysnand.
If you didn't pay attention to any of the guides here on GBATemp and never made a nand backup and never preserved your fuse count there is still hope for a downgrade (many guides on here to help you with that) but you will always have to boot to RCM and load a custom bootloader in order to boot your Switch after that because your fuse count won't match and there is no way to "unburn" a fuse.
If none of this makes sense to you then you shouldn't be attempting any kind of downgrade anyway.
Use hekate to find your fuse count and check here to see the current known fuse count for all firmwares.
Edit: Added fuse count list.
Black screens?
Just Switch logo and then nothing?
These are just a few examples of what you will face unless you fully understand what downgrading your switch means.
You cannot just willy nilly downgrade your switch to any firmware version that you find online and expect it to cold boot to official firmware without issues.
Your fuse count MUST match the firmware version that you are downgrading to and the boot0 and boot1 files that you use are console specific and firmware specific. If you just flash a firmware to your switch that you found online and it doesn't contain these console specific files and the fuse counts don't match then you are going to have issues.
Every time you cold boot your Switch to official firmware (not RCM and custom payload) the console checks to see if your fuse count matches the firmware that is on the sysnand. If you're booting a higher firmware than your fuse count then the Switch will just burn the fuses to match the higher firmware. If your firmware is lower than what your fuse count indicates then the switch won't boot at all. You'll only be able to boot at that point with RCM and a custom bootloader that ignores the fuse count.
If you previously updated your Switch using Choidejour and turned on AutoRCM then your fuse count should stay low enough for you to restore your nand backup that you made previous to upgrading the firmware on the sysnand.
If you didn't pay attention to any of the guides here on GBATemp and never made a nand backup and never preserved your fuse count there is still hope for a downgrade (many guides on here to help you with that) but you will always have to boot to RCM and load a custom bootloader in order to boot your Switch after that because your fuse count won't match and there is no way to "unburn" a fuse.
If none of this makes sense to you then you shouldn't be attempting any kind of downgrade anyway.
Use hekate to find your fuse count and check here to see the current known fuse count for all firmwares.
Edit: Added fuse count list.
Last edited by Kafluke,