acidentally formated my 3DS with SD card inside(gateway 9.2 installed). i have back up emunad and sysnad. do i do some kind of recovery with nand or do i have to reinstall gateway again?

before format sysnand is 9.2 emu is 9.4. hmmm just checked and it seem it is still sysnand is 9.2 emu is 9.4 and gateway still working. i guess i over reacted lol. btw should i upgrade to 9.5 emu nand? do i just release the file lancher.dat and update ?
how does this happen accidentally? lol