Never format a 2DS while on a version <6.0.0 or you will be unable to complete initial setup and will BRICK! i found this in the guide im following to install a9lh on my 2ds that had stock firmware. it was 6.0.0 with browser. i got as far as installing 2.1.0 but forgot to put in the wireless before I downgraded. i couldnt find a screw driver that worked at the time and so i popped a Zelda Ocarina cart in to see if the game was playable. it wasnt 1/2 playable because of the stretched screen on the firmware 2.1.0 meant for the o3ds and the 2ds wasnt made yet or la di da history. so i updated to 4.X from cart and im able to reach Decrypt9 from ds flash cart, but am trying to figure out the best way to downgrade back to 2.1.0 to then do the a9lh. does the sentence format mean in the 3ds settings in the home menu like memory card format option from there? or format like fowngrading a firmware from Decrypt9;? which i know probably isnt the latter but just wanna be safe and not brick!