How to Undo an Update on the Nintendo DSiby Seth AmeryUpdated September 22, 2017
Though you can install a new Nintendo DSi update at any time, the same can't be said for removing it. That means if you ever need to undo an update, you'll need to reset the device back to its original state. Similarly, you aren't able to partially update your device; if you don't want the most recent version, you cannot update the DSi.
Tap "System Settings" on the Nintendo DSi home screen. As the button tells you, this opens the system settings, which includes four pages of options. The one you need is on the last page.
Select "Format System Memory." This is located right underneath "System Update," which you may be familiar with by this point.
Tap "Format" each time the option comes up. The DSi will ask you three times if you're really sure you want to format the device, warning you of the consequences. After the third confirmation, the device begins formatting and returns to the dashboard upon completion.
These steps also apply to the DSi XL.
You'll need to establish your Internet connection again after formatting.
Any other changes you've made to the system settings, personal and otherwise, will reset. A reformatted Nintendo DSi is essentially the same as the day it came out of the factory.
Selecting "System Update" in the System Settings menu brings your console back up to the most recent software version.
When you reformat the hard drive, you cannot recover anything erased. Formatting is permanent.
Anything stored on the device will be lost, including downloaded software and any associated saves.
You will not be able to access online features without the latest software update.