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→GBA VC: Add information about CMACs on SD AGBSAVE copies
===NAND Savegame===
===NAND Savegame===
AGB_FIRM saves its active save memory to NAND on exit, this is then immediately picked up by NATIVE_FIRM on reboot by checking [[CONFIG_Registers#CFG_BOOTENV|CFG_BOOTENV]]. From there, this is verified and copied out to SD. The savegame format is as follows:
AGB_FIRM saves its active save memory to NAND on exit, this is then immediately picked up by NATIVE_FIRM on reboot by checking [[CONFIG_Registers#CFG_BOOTENV|CFG_BOOTENV]]. From there, this is verified and copied out to SD (also see below). The savegame format is as follows:
{| class="wikitable" border="1"
{| class="wikitable" border="1"
|-
|-
| Always 0xFF
| Always 0xFF
|}
|}
===NAND Savegame on SD===
A NAND savegame copied to the SD by process9 is identical to its counterpart on the NAND partition, save for the CMAC. For SD copies on retail units, the CMAC is recalculated as the AES-CMAC of the (SHA256 hash of ("CTR-SIGN" + Title ID (big endian) + SHA256 hash of ("CTR-SAV0" + SHA256 hash of (0x30..0x200 + the entire save itself)))), using keyslot 0x30 set up with the keyY from movable.sed. For SD copies on devkit units, the CMAC is recalculated using the SHA256 hash of 0x30..0x200 + the entire save itself, using a different key from process9 .rodata.