For those who are trying to get GC Action Replay to work:
You MUST patch using mios v4 if using an original or backup disc of AR (you have the option of choosing V4,v5, or v8 in the included mios patch) with the backup launcher Xi. It seems to only work with Original gamecube games currently. Alternatively, you should be able to use any mios with the AR Launcher (there's v1.08,v1.09, & 1.14 posted on Eurasia.nu). Again, it will only work with Original GC games. Maybe there will be support for AR in Backup Launcher 0.1 Upsilon.
I hex edited the action replay iso with the values in the action replay patches 1.3 (which allow the use of DVD-Rs) but it bypasses the load disc (it expects the backup to already be in there since the patches are intended for dols) so they do not work either with Xi.