region swap after region swap

hello everyone, i got a 3ds xl from japan in the mail. after following a guide, i ended up swapping it to EUR instead of US. whats the best way to approach this? already has fbi gm9 and luma. would i just need to get a ctr transfer image and write it to the nand with gm9? also, when i click the link for the ctrtransfer file, it doesnt direct me anywhere. it opens a tab with the hyperlink but nothing happens. thanks

UPDATE

i used the guide on 3ds.hacks.guide. Filled in the blanks where files were needed. Follow the guide step by step as you are messing with the ctrnand and can cause unwanted problems

Guide to Region Changing