Controllers were lagging when using IOS56 as a base for cIOSX rev20/21
XFlak had the great idea to replace the EHCI module from rev21 with the one from rev19 (the last version known no to have the controller lag), and the lag disappeared. (aka v21_lagfix)
Then, davebaol and xabby666 managed to modify the EHCI module from rev21 to fix the issue. They modified the code handling the watchdog preventing the hard drive to spin down.
You can now easily build WADs for these modified cIOSes (
v21d2x, for v21 davebaol/xabby666/XFlak) using to
XFlak's ModMii 4.4.7