You running tinyG or G2core?
No need with tinyG, the controller has onboard EEPROM, configuration changes are persistent.
But since you are asking, likely you are running G2core, where there is no persistent memory (yet).
There are at least 2 options
1. If you are a Chilipeppr user, the SPJS widget has an option to send a set of initialization commands to tinyG(G2core) on startup. Those could be parameter updates.
2. What I prefer to do is rebuild the G2core binary with a custom parameters.h file that has my specific configuration. Those defaults are loaded on restart, can be tweaked from there on.