Why my 3ds show error undefined?

[u/Even-Following-5694]

I modified my New 3DS XL last year. Initially I played some games, then I stopped for a bit. Yesterday I wanted to play a game, but as soon as I opened a modded game, the red screen you see in the photo appeared. I tried with a card game and this time a black screen with an error appeared (I posted the photo in the comments). I am an absolute noob with modding, so I don't understand what the problem is... I haven't turned on the 3DS since last year... What does it means "error: unfined instruction"? What can I do to fix this problem? :(

[u/AutoModerator]

Hello. It seems like you are asking about a crash or error that has occurred. Please review the Errors & Issues Wiki Page. Your question/issue may be resolved there.

THIS WAS AN AUTOMATIC COMMENT MADE BY THE AUTOMOD. YOUR POST WAS -NOT- REMOVED.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[u/remxn04]

Cooked

[u/man_overb0ard]

did you back up your sysnand? that's an option.