Here is what I did: SystemMenu 3.3Uv1 (so IOS30 is trucha patched). No previous IOS16 on the system. I obtained IOS16 v512 using NUS Downloader v1.1 and packed it into a WAD. Installed that: Title=1-10 (IOS16) vers: 2.0 (512) Using Sorg's modified WAD Manager 1.4 I attempted to install IOS16 v257 using IOS30 and got an error (-1035). Using Nicksasa's FSToolbox I dumped the TMD from 0000000100000010 to my SD card. Using a hex editor I changed the value at 0x1DC in the TMD to x0001. With FSToolbox I wrote the modified TMD to the NAND: Title=1-10 (IOS16) vers: 0.1 (1) Using Sorg's modified WAD Manager 1.4 I attempted to install IOS16 v257 using IOS30. Success: Title=1-10 (IOS16) vers: 1.1 (257) This means I was able to successfully install IOS16 v257 on a system that already had IOS16 v512 using a trucha patched IOS. I have no idea if this would work on a virgin 4.0 Wii, but it may be worth a try. Also since the LU64+ Wii's don't seem to have any trouble using IOS16 v257 this may be a way to install cIOS 4.0 systems without using the DVDX installer.