Hacking Sky3DS/DiskWriter - EEPROM vs NAND

[markmcrobie]

When you load ROMs into DiskWriter there's a column called "EEPROM" and some games say Yes and some say No. The ones that say No also came up with a message when they were loaded into DiskWriter saying "This ROM is a NAND type" as opposed to "This ROM is an EEPROM type".

What's the difference, and what's the impact?

Animal Crossing - New Leaf is one example I have where it says "EEPROM = No".

Thanks

 

[WulfyStylez]

'EEPROM games' store the save on a separate EEPROM chip. These are referred to as 'Card 1' games.
'NAND games' store the save on the same (NAND) chip as the game itself, in a small writable portion. These are referred to as 'Card 2' games.

The impact is that you can't trim Card2 games as it'll break their ability to save. Beyond that, there's not much of a difference to the end user any more.

 

[markmcrobie]

Thanks, so how would I trim an EEPROM game? Or conversely how would I make sure the NAND games are NOT trimmed?

 

[WulfyStylez]

https://gbatemp.net/threads/3ds-rom-tool-rom_tool.349314/

 

[markmcrobie]

Can NAND type games still have their save data backed up using DiskWriter?

 

[DjoeN]

Can NAND type games still have their save data backed up using DiskWriter?

Yes,

In Diskwriter, choose backup rom, it backups the whole rom including the part where it saves., to get it back, write THAT backup again to your Sky3DS.

TIP:
It's always wise to start another game and close it, before removing it from the sd, this way you are sure to have the save written to the nand/eeprom.

 

[markmcrobie]

Ok thanks. So in general use, NAND vs EEPROM makes no difference to how an ordinary user uses Sky3DS?

 

[DjoeN]

No, it only takes longer to backup the save cause you need to backup the rom
That's all

 

[markmcrobie]

Yes,

In Diskwriter, choose backup rom, it backups the whole rom including the part where it saves., to get it back, write THAT backup again to your Sky3DS.

TIP:
It's always wise to start another game and close it, before removing it from the sd, this way you are sure to have the save written to the nand/eeprom.

With regards to your tip, do you recommend actually starting another game, then closing it or is it enough to simply use the blue button to switch to a new game?

 

[DjoeN]

Could be, never tested it that way