if you checked the compatibility list on wiki, I thought I wrote some information to explain what's needed to use old cIOS.
but if not present :
1. waninkoko cIOS installer always install in both 249+250 (duplicate)
you can :
install, dump (bluedump mod), edit the slot number (ShowmiiWad), reinstall (wad manager), reinstall d2x to common slot
or
use modmii to get and set a slot number, then install (wad manager)
or
install d2x in another slot and keep rev19 in 249/250 (you know, all loaders let you choose the slot to use, they don't NEED to be 249 or 250, it could be anything in range 230-253)
2. to not see "use d2x" when trying to launch emuNAND, you need to comply to old cIOS requirement :
dump on root (no subfolders)
512 bytes/sector
etc.
I really thought I explained that on the wiki.
If you want the ultimate setup, it will require some time to create, but you should consider this:
512b/sector hdd, Single MBR FAT32 partition (up to 16TB), with all Wii, gamecube, NANDs, emulators, etc.
1. Install many different cIOS version/base (the one you need based on wiki compatibility):
hermes cIOS 4 and 5.1 (in usual slots)
cIOS rev17, rev18[x], rev19[x], rev20b[x], d2x_vx [x] (different version too)
2. multiple NAND path, one per region. (sometime, region free patch is not enough)
/nands/pl_us/ <-- install ALL games from all regions here (all the working AND non working ones)
/nands/pl_eu/ <-- install PAL games not compatible with region free
/nands/pl_jp/ <-- install JP game not compatible with region free
/ <-- root for games using old cios only (unfortunately, only one dump per root, so you can use both sd and usb to get 2 different roots)
Note: "pl_" comes from common usages of using multiple NAND region with "Post Loader" (pl)
5. setup sneek on SD and Uneek on USB
USBLoaderGX can fully recognize both at the same time (unlike other booting method)
set expecting settings in each nands from hidden menus (region free, forced video mode, etc.)
You might even want to use a "nands/pl_480i/" for games not working in widescreen and/or 480p, or anything else than 240p
4. setup USBLoaderGX to display pl_us as default path
set each game setting to use :
- correct NAND path based on its region if not working
- either cIOS mode or neek mode
- correct cIOS slot (if using cIOS mode)
The only issue with this setup can happen for few games if they are on a partition bigger than 2TB, some games check the NAND free space and doesn't get proper size if too big prompting an error in system file at game launch. it usually affects only the first launch, to create the savegame file. once created, accessing files seems to not be an issue anymore. you can create the savegame on SD card's emuNAND path, then move the dump to a bigger partition if needed.