I have experienced this save issue even when I constantly use the *+START hotkey.
Because of this,
I've used the *+START hotkey along with using the *+L hotkey afterwards and returning to file list, and I've done so at least 20 times since I lost my save file. Since then, I have experienced no save data loss.
So whenever you are done with the game:
1. *+START to dump the save
2. *+L to return to menu
3. Select the "return to file list" selection to ensure save data retention.
Do all of this BEFORE turning off your K101 unit, never turn it off at any other time unless you want to lose your save data.
Because of this,
I've used the *+START hotkey along with using the *+L hotkey afterwards and returning to file list, and I've done so at least 20 times since I lost my save file. Since then, I have experienced no save data loss.
So whenever you are done with the game:
1. *+START to dump the save
2. *+L to return to menu
3. Select the "return to file list" selection to ensure save data retention.
Do all of this BEFORE turning off your K101 unit, never turn it off at any other time unless you want to lose your save data.