DSi System Update 1.4.2

News via http://hackmii.com/2011/05/dsi-system-update-1-4-2/

Update: 25/05/11 An updated Sudokuhax(final update) will be released at the same time as the final DSiWareHax, but if you already have Sudokuhax and want to copy this updated Sudokuhax to “internal memory” you must still be on 1.4.1.(or below) This updated Sudokuhax and the final DSiWareHax uses an updated SD card loader, changes include faster boot.nds loading among other things.

DSi system update 1.4.2 blocks copying all current and future DSiWare exploits to “internal memory”. Most of you won’t have the final DSiWareHax target, but don’t update for now anyway. Only people who already have the target game, and stay on system version 1.4.1(or below) until exploit release could copy the exploit to “internal memory”. DSiWare savedata exploits are dead with system update 1.4.2, after the release of this exploit later, there will be no more DSiWare savedata exploits.

The EC certificate APCert in the DSiWare on SD card signs the hashes stored in the DSiWare on SD card, this includes hashes of savedata among other things. This APCert is signed by the console-unique TWCert, this cert is signed by Nintendo. This TWCert is stored in NAND.

The initial system settings title verified the APCert with the TWCert contained in the DSiWare stored on SD card. This allowed us to modify DSiWare savedata, since we could resign the APCert with any TWCert from other systems. The new 1.4.2 system settings title verifies the APCert with TWCert stored in NAND. This stops us from modifying DSiWare savedata for arbitrary systems, as the only way to get those system certs is from NAND. When you don’t already have DSiWareHax, it’s impossible to obtain your system certs without soldering NAND. The new system settings will not allow any DSiWare on SD card signed by other systems to copy to “internal memory”.