Rules #1 :
NEVER EVER USE FLASHDRIVE WITH USBLOADERS !
And that's all for the rules
Actually, never use them with Wii and WiiU, they are not compatible with any homebrew. Even Nintendo officially recommended on their website/FAQ to NOT use flashdrives, even though the reason is different.
Then there are tips :
Tips #1 : if you use a WiiU (instead of a Wii), you need y-cable to get power from 2 USB Port if your drive is not externally powered.
Tips #2 : Don't use d2x r53 (this is the latest, and LAST IS NOT BETTER !). prefer d2x v8 (on wii) or d2x v10 r52 (on vWii).
Tips #3 : always use port 0 (bottom on Wii, back-top on wiiU), and don't plug more than one HDD at the same time. (exception with WiiU HDD, which is skipped by usbloaders).
Tips #4 : if your HDD (not flashdrive) still have detection issue and is stuck or skipped at the 20sec init screen, go to usbloader settings and set the "loader' IOS" to 58.
Tipc #5 : you better use Wiitdb to get proper game's titles. settings>update>wiitdb. Then go to Settings>features>and enable "use gametdb".
You don't need to try slot250, the new modmii setup already installed the better version of cIOS d2x v8 final base57 directly in slot 249.
all guides and user's suggestions found on internet telling you to "use 250" is based on the fact the better version was installed in 250 instead of default slot for 10 years....
you already have "base57" (the best version) in default slot now.
If you really really really can't use a real external HDD (why not buy one?), and you only have a flashdrive, then you can try to format the flashdrive to WBFS format.
once in WBFS format, NEVER EVER use "WBFS manager" program, but use "wii backup Manager" instead.
you can't put anything but Wii games on it. (no gamecube, no emulators, rom, wads, etc.)
But just know that WBFS is not a fix, it's a workaround : the flashdrive will work fine in read mode, but will STILL freeze when trying to dump a disc to usb. Write mode is broken and unsupported on flashdrives.
For wad install :
https://gbatemp.net/posts/6592730
quick setup in 3 steps :
- go to settings > features > dump NAND > full
- go to settings > features > WAD manager to install wads to that dump copy now located on SD:/nands/01/ folder
- main window > top menu > 4th icon > enable "channels on emuNAND"
Done