Talk:Flash Filesystem

• Can't help with nand reading but lib references give some indication of the filesystem.

Note! some of these NAND paths below may be outdated. Confirmed NAND directories/directory structures are on the Flash Filesystem page.

nand:/extdata

nand:/ro/

nand:/ro/sys/HWCAL0.dat

nand:/ro/sys/HWCAL1.dat

nand:/rw/

nand:/rw/sys/

nand:/rw/sys/config

nand:/rw/sys/updater.log

nand:/rw/sys/PlayHistory.dat

nand:/rw/sys/PedometerHistory.dat

nand:/rw/sys/LocalFriendCodeSeed

nand:/rw/sys/SecureInfo

nand:/title

nand:/title/%08x/%08x

nand:/title/%08x/%08x/%08x.app

nand:/title/%08x/%08x/title.tmd

nand:/ticket

nand:/ticket/%08x/%08x.tik

nand:/tmp

@yellows8, since the \titles directory is similar between nand and sdmc, do you think it should have a separate page from the SD Filesystem page?--3dsguy 02:36, 23 August 2012 (CEST)

Go ahead.(SD/NAND /title is exactly the same, except for the additional encryption for SD perhaps) NAND has .db files too, but I'm not sure where those are located. --Yellows8 02:59, 23 August 2012 (CEST)

Possible firmware downgrade vulnerability

Please correct where I'm wrong. Assume we have NAND-dumps from two 3DS units A and B for both firmware versions X and Y. I.e. 4 data sets AX, AY, BX, BY. Assume that all clear data is identical for the same firmware version or unique per console and stay untouched with firmware version change (i.e. AX, BX is a brand-new console with a factory reset dumps and AY, BY have just updated firmwares). Then AX xor AY = BX xor BY and BX = BY xor AX xor AY.

There's no way to convert a NAND image from one 3DS for use on another 3DS, without generating the NAND xorpad(s) for both systems(requires ARM9 code exec on both). Another reason why ARM9 exec is needed here is because there's certain files stored in CTRNAND containing console-unique AESMACs. Since that keyslot is initialized by bootrom those AESMACs can only be calculated on the same 3DS which you're calculating these CTRNAND AESMACs for. --Yellows8 18:02, 10 April 2014 (CEST)

I'm not about converting a NAND image from system to another directly. Can we alculate for a various firmware byte-to-byte XOR-difference, which result the same xorpads for each system to annihilate. And for the same CTRNAND files untouched with a firmware update this difference will be zero. So applying this difference for another console CTRNAND will update a firmware without the need of the actual console-unique xorpad--Duke srg 21:48, 10 April 2014 (CEST)

The CTRNAND files /w console-unique AESMACs I'm referring to get updated when sys-updates get installed, if those don't get updated properly(invalid AESMACs for example) you would have a system which would fail to boot when it tries to launch titles from CTRNAND-FS. There's no way to properly update those files without proper NAND xorpads/etc. --Yellows8 22:11, 10 April 2014 (CEST)

Ok, just to clarify, during system update AESMAC init file IS updated with the new console-unique data. So after transferring firmware changes from one system to another without complete decypher, during next boot at least AESMAC file on CTR NAND partition contents will have wrong data and REG_AESMAC being initialized with that will fail the following boot process. Smart enough.--Duke srg 05:59, 11 April 2014 (CEST)

Yeah, at least one of those console-unique AESMACs would be rendered invalid with method you're describing. --Yellows8 06:21, 11 April 2014 (CEST)