Crossplay XX/GU

XX 3DS Crossplay with Switch GU

1. First download this boot.firm with a .plg plugin loader. It's Luma Version 9.1: https://www.mediafire.com/file/11ca181iacfwbry

2. Then move it to the root of your 3DS SD-Card and overwrite the current boot.firm or rename the current boot.firm to boot.firm.bak or anything similar.

3. Next is the cheat itself. For that you first need this blank ctrpf.plg: https://gbatemp.net/attachments/actionreplay-7z.110980/
Create a folder called "plugins" inside the Luma folder on your SD-Card, please note it's plural so make sure it's spelled exactly this.

4. Next, create another folder with thr XX Title ID inside it, the ID is 0004000000197100. Now move the previously downloaded .plg in that Title ID folder and rename the plugin to "plugin.plg", please note that .plg in this case is the file extension, not included in the name.

5. Then create a new .txt file also in the Title ID folder and call it "cheats", so it's cheats.txt.
Copypaste this into the .txt file, don't add or change anything.
[Region switch v1]
003DA3C8 E3A08002 // change region to european
003795C0 EA21E3E6 // branch to patch
00BF2560 E35200AC // compare if this is hubParam packet by its size
00BF2564 1A000003 // jump to return if not equal
00BF2568 E3A02030 // first part of hubParam size
00BF256C EBDBC5F6 // branch with link to __aeabi_memcpy4
00BF2570 E2811008 // add 0x8 to source to bypass problematic bytes
00BF2574 E3A02074 // second part of hubParam size
00BF2578 EBDBC5F3 // branch to __aeabi_memcpy4
00BF257C EADE1C10 // return from patch


6. Now insert the SD-Card back into your 3DS and press in the homemenu L+Down+Select for opening Luma or whatever keycombo you changed it into and enable plugin loader. Then boot into MHXX, screen should flash green and you should get a "Plugin ready" on the topscreen in the bottom right corner. If you don't get that then you did something wrong, check the steps.

To open the plugin press Select and then tap on "ActionReplay" in the touchscreen menu and tick the displayed cheat by pressing A. Congrats, you now have crossplay!

Common issues:
Do not post event quests and don't join hubs hosting event quests, you will crash.
Do not wear/use XX specific DLC armor/weapons which are dummied out in GU, like USJ armor or the fire DBs.
Do not send GCs with XX DLC armor equipped.
You can't join hubs with IDs as they'll ask for a password regardless if the actual hub has one or not.
You can't host your own hubs for GU.