After battling for many hours trying to make metroid prime trilogy to work, I finally did it! ... sort of =/
First of all I never had any problems loading metroid prime 1. My problems were with 2 and 3. I have cios38 rev14 with usb loader gx r844. I downloaded hermes cios222 and installed 222 as 37/38 and 223 as 60/37( or was it 38?). That didnt solve the problem so I tried this method with wiiscrubber and renaming the dol files. Now I can load also metroid prime 2! ... but still cant metroid prime 3.
What I have done is I have left the renamed mp2_p.dol in the root of the sd card. That way if I want to play mp2 I will just choose alternate dol and select that one ( 781 ), and if I want to play mp1 I can just select "default" in alternate dol settings in USB GX, and load it from the menu. I guess I can get just a mp3 corruption ISO, load it and wont experience any farther problems since the original is not dual layer.
I have a question though. Is there a way to get the main menu screens and options? Like to adjust controls, bonuses, select mii, select difficulty, etc ?? Or just loading the game directly is the best one can get when playing the game via a usb ehd?