How to Convert 4GS and DSZ save files to and from SAV

4GS

This is just a renamed version of the emulator VBA-Next's srm save format.

More details on VBA's save format can be found on emugen wiki.

Convert 4GS to SAV

To convert it to sav: just use gbaconv-web.

Convert SAV to 4GS

Run the sav file through gbaconv-web, then rename the output from ".srm" to ".4gs".

DSZ

This is Desmume's dsv save format compressed to gzip.

Convert DSZ to SAV

1. Install an adblocker if possible. Android users can install extensions with Kiwi Browser or Firefox
2. Extract the uncompressed save file with 7-Zip or this online extractor.
3. The extracted save file wont have an extension, but it is still a dsv file. Use this website to convert it to sav (many ads; if you don't have adblock, be careful. You need to click the grey "convert" button).

Desmume uses dsv files, and MelonDS can use dsv files by clicking "File > import savefile"; so if you plan to use your save file with either of these emulators, you can skip step 3.

Convert SAV to DSZ

DS Player is capable of loading .sav files, so the below steps may not be neccessary.

1. If your save file is not a dsv, convert it to dsv using this website (many ads; if you don't have adblock, be careful. You need to click the grey "convert" button)
2. Compress the dsv file to gzip using 7-Zip or this online compressor.
3. Rename the gzipped file to ".dsz" and load it into DS Player.

Even after following these steps, it may still be impossible to import your save into DS Player. DS Player, being a fork of Desmume, has the same issues with guessing save file size. In Desmume, this is not a problem because the user can choose the correct file size when importing .sav files; however, DS Player has no such option, so any .sav (or .dsz) that is a greater size than what DS Player expects will always fail to load.

About 4DSAZ, 4GZ, and 44GBASAV files

44670's web emulators use even more unique file types if you connect the web app to Dropbox. These Dropbox-exclusive file types, 4DSAZ and 4GZ, are even harder to convert to and from sav, so please do not use save files from Dropbox, only use the save backup options in the emulator menu (which is accessed with esc on keyboard).

The 44GBASAV file type is identical to srm and 4gs.