No disrespect to you. But I can't understand what you're saying. Can you explain as if you're explain to 10 year old? So IOSU would work on 5.5.0 and 5.5.1 right?
ITs simple, games has not been able to direct request exec or rw access to external ports in the WIIU, those attributions are in a ANCAST layer controlled by the IOSU, this mean when a game need to write on a device, it request to IOSU that request to ANCAST that enable NVRAM position.
In PS4 NVRAM are EXCLUSIVE TO A GAME.
In PS3 it is WORLD exclusive.
In WiiU the ANCAST is the WORLD EXCLUSIVE
In WIIU only in MarioMaker the NVRAM has not REALOAD from the real flash back to NVRAM, so, the EXECUTION code on USB ports are still there, so, when the call to a SYMBOL in the shadow NVRAM (or simple the current memory NVRAM) it will OPEN the usb do RW, and ALSO will let you EXECUTE a SIGNED CODE!
IT doesnt allow you to run a UNSIGNED CODE... so, if you have download a game to USB from eshop, you CAN call from the EXPLOIT it to RUN.....