Install Luma as usual, download Decrypt9 https://github.com/d0k3/Decrypt9WIP/releases, copy the .firm version to SDCARD:/luma/payloads (name it left_decrypt9.firm). reboot 3ds holding left. Once in Decrypt9 go to system nand, dump local friend seed, follow prompts, profit.
Dump all 3 but don't...