From
http://wiki.gbatemp.net/wiki/3_in_1_Expans..._for_EZ-Flash_V
Whenever I load up a game, my save is gone! What do I do?
This kind of issue can only be resolved through troubleshooting. Does the GBA ROM require SRAM patching beforehand? If so, make sure you are SRAM patching your games using one of the two tools listed in the initial setup section. If you are already doing this, make sure you are loading games in either PSRAM or NOR, not both. From what I have seen, most loaders want you to use one or the other for it to work correctly. If you’ve tried everything else and your GBA roms still aren’t saving/loading properly then the problem may be that the battery (the thing inside the cartridge with yellow rubber coating) isn’t working. The save feature will not work without the battery. Try using GBAExploader, if it asks ”may I set this slot2 expansion pack for GBAExploader” every time you load it up then the battery is definitely broken. You now have 2 options:
1) Get a new ezflash 3-in-1 and hope the battery in that one isn’t stuffed as well
2) Replace the battery yourself. Here’s a good tutorial I’ve found
http://gbatemp.net/index.php?showtopic=132872
Check the help files of your loader for more information (such as known bugs, proper ROM loading procedure, etc.).
Edit: Here's more:
Hardware Features
256 Mb (32 MB) of NOR Flash Memory(512 Mb/64 MB on the third revision). This type of memory is able to retain data without requiring uninterrupted power. Depending on data size, writing may take up to several minutes. One typical use includes copying over a GBA ROM, thereby allowing the 3-in-1 to act like a real GBA cartridge.
128 Mb (16 MB) of PSRAM. This memory does not retain data when the power is turned off. However it can be written at speeds much faster than NOR memory.
4 Mb (512 KB) of battery backed SRAM for save data. The battery is necessary to retain data.
Programmable embedded "rumble pak" (haptic feedback) device