syscheck is not needed to debug DM(L) issues. DIOS MIOS doesn't use cIOS at all, it use only the MIOS. If you want to help the user, only knowing which MIOS version he installed should be enough. using syscheck doesn't give the MIOS version (see, this syscheck version only detects version up to 2.6.1, even if he has 2.10 installed)
All the useful thing syscheck can give you is BC version (should be v6).
the used USBLoader has nothing to do (I tested this issue with wiiflow, dmbooter and usbgx, it happens in all three of them)
USBLoaderGX version is good (as long as it's >r1197)
His problem is the HDD.
Look everywhere in the forum, a lot of users have the shutdown problem.
It's a random issue caused by your Hard drive, all you can do is try again.
Sometime it works after few tries. if it really doesn't work, then check your HDD format/partition/etc. (but if USBGX let you launched the game, it should be correctly setup).
It can be that this drive is not compatible with DIOS MIOS. Try another device (flash drive, hdd, etc.) or use DML+SD card.
Edit:
It could be video mode problem too (though, it should only blackscreen after slpashscreen). Did you force a different video mode, or did you use "DML Auto"?
Just curious but have you tried with another loader? Wiiflow or CFG USB Loader, checking that the No Disc+ Patch is enabled.
Just for information, the "No Disc" and "No Disc+" settings are not used anymore.
No Disc is unused since DML v1.0
No Disc+ is used only by DM(L) v2.2 (it is automatically enabled when needed in DM2.3+)