This is not a project or something I am working on, asking for help, or someone to make or get involved with. Is just simply information about my understanding of how things work, break down to share with others who are willingly interested. Well some people may click this thinking of something i have yet to acknowlede but is nothing that needs negative attention, this is just some information i collected that i hope may help someone in the future who may want to invest time into this. So I got a ps2 game on ps4, is Rouge Galaxy. Anyway, we all are familiar with the ps3 and ps4 being able to play ps2 games either through backwards compatibile models of ps3 or purchase on psn on both. While this is posted in the ps4 section of the forum, i will talk about that part in a moment. But i just feel is necessary to highlight the ps3 save format quickly thinking it may help make things easier to understand. About ps2 save data on ps3 systems. Using the ps3 backward compatibile model for example, these models have the necessary requirements to play ps2 formatted disc in the disc drive. You can also buy a game from Playstation store to play and is installed on the Hard disk drive. The point here is they work but the save is formatted in two seperate ways. Ps2 game disc requires you to go to the xmb home menu under memory card save data and create one of 2 memory cards, one is ps1 and other ps2. Is the default sizes. (PS1 uses 15 "Blocks" Ps2 uses 8MB of storage) You are required to do so when playing the ps2 disc games. The save format is actually different than of other ps2 players like the PCSX2 emulator for computers or the different save data formats of cheat deveices like action replay, code breaker or game shark, even the original PS2 console itself has different format which if you have some kind of homebrew enable system you can extract from the official memory card or some external card reader for pc (probably more but i made my point) The ps2 games downloaded from PSN uses altered save format, instead of creating virtual memory card the game is loaded with is own set of memory cards and saved in seperate way. Each downloaded game has is own set of two 8MB cards inserted at all times, which is different than having a single virtual memory card and any kinds of games you play can be saved into it. The two memory cards are exclusive to each game so no other game can save data onto it. To make it easy to understand. PS2 disc games = save to created virtual memory card PS2 download games = Save to exclusive memory cards paired when game is loaded It cannot be changed but there is save editors and converters that can allo you to inject the save data into the other format with pc programs. Now that the ps3 explanation is out of the way this is about ps4, going back to when i said i got a ps2 game Rouge Galaxy, i played it and it works well, i was also curious about save data injection so i decided to explore, i found out is possible to back up save data and so i did it. But what i found is rather interesting. The save data is about 18MB which is rather large for a PS2 game, but why? Well based on the file structure it only shows a bunch of folders but with 2 files. I would assume is just like ps3 was but is not. the ps3 has 4 files for the PSN download games, with a .MEC extention for two of them, these files are the memory card data. Each file represents is own memory card. So why mention that, well looking at the ps4 save data, it has only 2 files. One of them has no extention with the Game's title id and another one does with is only 96KB... The only idea i got out of that is the two virtual memory card data is merged into the one file making it the total of 18MB. Now i know currently there isn't any editors or converts or extractors, decryptor stuff for this yet but the file contains both virtual memory card data for one game. I was wondering why but is probably not important, i just figured it be more like the ps3 since the console already seem to have ps2 games functional so did't expet this change. But the thing i know now is the data is in the file and may not be easy to break down to more user managaeable format. So the possible goals include Seperate the memory card data into manageable files (To use with existing ps2 save data managers i guess) Decrypt files (For save data editing, extracting, or injecting, sharing, or converting) Create a way to possibaly injecting save data into the system of any format. Again, just all information i came up with for anyone who is interested, i'm not asking for anything from anyone, just sharing this in case someone was curious. So then if such things could be done, then the save data can be preserved maybe from official ps2 memory cards, the PCSX 2 emulator, ps3 compatibility and ps4 as well.