I have a (virgin) 4.3E black WII with latest Sundriver. While i enjoy my ability to play from a built in Hard Drive, firmware 4.3 prevents me from using a GC menu and from playing US/NTSC backups! These are my reasons for downgrading to 4.1. I am planning on following 4.3 SoftMod Guide by mauifrog.

Does anyone has any experience or enough understanding of the process to answer the following question:
Do i need to put my DVD drive back and use the original DVDs of either "
Lego Indiana Jones Original" or "Yu-Gi-Oh! 5D''s Wheelie Breakers"? Or (because i have Sundriver) will backup ISO's do the trick?

I don't dare to try it myself yet