So I've never been entirely clear: what, exactly, does installing HiyaCFW change on a DSi? And can it be removed without a trace afterwards? Is it like the 3DS where uninstallation still leaves traces behind and carries a substantial risk of an unrecoverable brick?
I personally are not very happy with uninstalling CFW. Uninstallation of CFW always carries some kind of risk. By patching out signature checks you can run all sorts of code – including a modified Home Menu on the 3DS. Removing the signature patches (=re-enabling the checks) will make the console refuse to execute the Home Menu → paperweight.
There is no reason why the same method of bricking should not be possible on a DSi. However, simply installing unlaunch (coldboot exploit; signature patches) followed by an uninstallation
should not do any harm. I have encountered the following reason for the wish of uninstalling unlaunch:
In addition to the signature patches virtually everybody on this forum wants, unlaunch applies
non-optional patches:
- No Health and Safety warning screen
- No music and no sounds in the official “Launcher”
Using HiyaCFW(-helper) with or without TWiLight Menu++ is
NOT a modification on the system – it entirely exists on SDNAND (“EmuNAND”).
Removing the SD fully removes HiyaCFW.
I’m not aware of any (currently widely used) software, other than unlaunch itself, that modifies the DSi NAND.
However, you could – in theory – modify a NAND backup on a computer e.g. with twlnf, and flash it back to the DSi (
DON’T!! twlnf is unsafe!! This alone can lead to a brick!). I guess a modification on “Launcher” would make a DSi brick on uninstalling unlaunch. Sadly I can’t do any experiments in this direction because I lack the soldering skills for a DSi hardmod to have the same level of safety ntrboot provides on the 2/3DS.